Fix library detection under shells whose echo does not expand escapes

The OpenSSL, wolfSSL, PCRE2 and PAM probes built their test program with
echo "...\n...". make runs recipes through /bin/sh, which is dash on Debian
and Ubuntu, where the builtin echo expands \n. On distributions where /bin/sh
is bash - every RPM based distribution, and macOS - it does not, so the probe
compiled

    #include <openssl/ssl.h>n int main(){return 0;}

which is not valid C. Every probe therefore failed and the build silently
dropped TLS, PCRE2 and PAM support with no diagnostic.

Use printf, which expands escapes the same way everywhere.

Makefile.FreeBSD

@@ -52,14 +52,14 @@ ifeq ($(LIBSTATIC), true)
     STATIC_SUFFIX = -Wl,-Bdynamic
     ZLIB = -lz -lzstd
 endif
-WOLFSSL_CHECK ?= $(shell echo "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testwssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestwssl testwssl.o $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX) 2>/dev/null && rm testwssl testwssl.o && echo true||echo false)
+WOLFSSL_CHECK ?= $(shell printf "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testwssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestwssl testwssl.o $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX) 2>/dev/null && rm testwssl testwssl.o && echo true||echo false)
 ifeq ($(WOLFSSL_CHECK), true)
     LIBS += $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX)
     CFLAGS += -DWITH_SSL -DWITH_WOLFSSL
     SSL_OBJS = ssllib$(OBJSUFFICS) ssl$(OBJSUFFICS)
     ZLIB :=
 else
-OPENSSL_CHECK ?= $(shell echo "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestssl testssl.o $(STATIC_PREFIX) $(ZLIB) -lcrypto -lssl  $(STATIC_SUFFIX) 2>/dev/null && rm testssl testssl.o && echo true||echo false)
+OPENSSL_CHECK ?= $(shell printf "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestssl testssl.o $(STATIC_PREFIX) $(ZLIB) -lcrypto -lssl  $(STATIC_SUFFIX) 2>/dev/null && rm testssl testssl.o && echo true||echo false)
 ifeq ($(OPENSSL_CHECK), true)
     LIBS += $(STATIC_PREFIX) $(ZLIB) -l crypto -l ssl $(STATIC_SUFFIX)
     CFLAGS += -DWITH_SSL
@@ -68,13 +68,13 @@ else
     ZLIB :=
 endif
 endif
-PCRE_CHECK ?= $(shell echo "\#define PCRE2_CODE_UNIT_WIDTH 8\\n\#include <pcre2.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpcre.o - 2>/dev/null && $(CC) -o testpcre testpcre.o $(LDFLAGS) -lpcre2-8 2>/dev/null && rm testpcre testpcre.o && echo true||echo false)
+PCRE_CHECK ?= $(shell printf "\#define PCRE2_CODE_UNIT_WIDTH 8\\n\#include <pcre2.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpcre.o - 2>/dev/null && $(CC) -o testpcre testpcre.o $(LDFLAGS) -lpcre2-8 2>/dev/null && rm testpcre testpcre.o && echo true||echo false)
 ifeq ($(PCRE_CHECK), true)
     CFLAGS += -DWITH_PCRE
     PCRE_OBJS = pcre$(OBJSUFFICS)
     PCRE_LIBS = $(STATIC_PREFIX) -lpcre2-8 $(STATIC_SUFFIX)
 endif
-PAM_CHECK ?= $(shell echo "\#include <security/pam_appl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpam.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testpam testpam.o -lpam 2>/dev/null && rm testpam testpam.o && echo true||echo false)
+PAM_CHECK ?= $(shell printf "\#include <security/pam_appl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpam.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testpam testpam.o -lpam 2>/dev/null && rm testpam testpam.o && echo true||echo false)
 ifeq ($(PAM_CHECK), true)
     PLUGINS += PamAuth
 endif

Makefile.Linux

@@ -60,14 +60,14 @@ ifeq ($(LIBSTATIC), true)
     ZLIB = -lz -lzstd
 endif
 
-WOLFSSL_CHECK ?= $(shell echo "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testwssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestwssl testwssl.o $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX) 2>/dev/null && rm testwssl testwssl.o && echo true||echo false)
+WOLFSSL_CHECK ?= $(shell printf "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testwssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestwssl testwssl.o $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX) 2>/dev/null && rm testwssl testwssl.o && echo true||echo false)
 ifeq ($(WOLFSSL_CHECK), true)
     LIBS += $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX)
     CFLAGS += -DWITH_SSL -DWITH_WOLFSSL
     SSL_OBJS = ssllib$(OBJSUFFICS) ssl$(OBJSUFFICS)
     ZLIB :=
 else
-OPENSSL_CHECK ?= $(shell echo "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestssl testssl.o $(STATIC_PREFIX) $(ZLIB) -lcrypto -lssl  $(STATIC_SUFFIX) 2>/dev/null && rm testssl testssl.o && echo true||echo false)
+OPENSSL_CHECK ?= $(shell printf "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestssl testssl.o $(STATIC_PREFIX) $(ZLIB) -lcrypto -lssl  $(STATIC_SUFFIX) 2>/dev/null && rm testssl testssl.o && echo true||echo false)
 ifeq ($(OPENSSL_CHECK), true)
     LIBS += $(STATIC_PREFIX) $(ZLIB) -lcrypto -lssl $(STATIC_SUFFIX)
     CFLAGS += -DWITH_SSL
@@ -76,13 +76,13 @@ else
     ZLIB :=
 endif
 endif
-PCRE_CHECK ?= $(shell echo "\#define PCRE2_CODE_UNIT_WIDTH 8\\n\#include <pcre2.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpcre.o - 2>/dev/null && $(CC) -o testpcre testpcre.o $(LDFLAGS) $(STATIC_PREFIX) -lpcre2-8 $(STATIC_SUFFIX) 2>/dev/null && rm testpcre testpcre.o && echo true||echo false)
+PCRE_CHECK ?= $(shell printf "\#define PCRE2_CODE_UNIT_WIDTH 8\\n\#include <pcre2.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpcre.o - 2>/dev/null && $(CC) -o testpcre testpcre.o $(LDFLAGS) $(STATIC_PREFIX) -lpcre2-8 $(STATIC_SUFFIX) 2>/dev/null && rm testpcre testpcre.o && echo true||echo false)
 ifeq ($(PCRE_CHECK), true)
     CFLAGS += -DWITH_PCRE
     PCRE_OBJS = pcre$(OBJSUFFICS)
     PCRE_LIBS = $(STATIC_PREFIX) -lpcre2-8 $(STATIC_SUFFIX)
 endif
-PAM_CHECK ?= $(shell echo "\#include <security/pam_appl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpam.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testpam testpam.o -lpam 2>/dev/null && rm testpam testpam.o && echo true||echo false)
+PAM_CHECK ?= $(shell printf "\#include <security/pam_appl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpam.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testpam testpam.o -lpam 2>/dev/null && rm testpam testpam.o && echo true||echo false)
 ifeq ($(PAM_CHECK), true)
     PLUGINS += PamAuth
 endif

Makefile.Solaris

@@ -31,20 +31,20 @@ COMPATLIBS =
 MAKEFILE = Makefile.Solaris
 PLUGINS = StringsPlugin TrafficPlugin TransparentPlugin FilePlugin
 
-WOLFSSL_CHECK = $(shell echo "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testwssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testwssl testwssl.o -lwolfssl 2>/dev/null && rm testwssl testwssl.o && echo true||echo false)
+WOLFSSL_CHECK = $(shell printf "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testwssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testwssl testwssl.o -lwolfssl 2>/dev/null && rm testwssl testwssl.o && echo true||echo false)
 ifeq ($(WOLFSSL_CHECK), true)
     LIBS += -lwolfssl
     CFLAGS += -DWITH_SSL -DWITH_WOLFSSL
     SSL_OBJS = ssllib$(OBJSUFFICS) ssl$(OBJSUFFICS)
 else
-OPENSSL_CHECK = $(shell echo "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testssl testssl.o -lcrypto -lssl 2>/dev/null && rm testssl testssl.o && echo true||echo false)
+OPENSSL_CHECK = $(shell printf "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testssl testssl.o -lcrypto -lssl 2>/dev/null && rm testssl testssl.o && echo true||echo false)
 ifeq ($(OPENSSL_CHECK), true)
     LIBS += -l crypto -l ssl
     CFLAGS += -DWITH_SSL
     SSL_OBJS = ssllib$(OBJSUFFICS) ssl$(OBJSUFFICS)
 endif
 endif
-PCRE_CHECK = $(shell echo "\#define PCRE2_CODE_UNIT_WIDTH 8\\n\#include <pcre2.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpcre.o - 2>/dev/null && $(CC) -o testpcre testpcre.o $(LDFLAGS) -Wl,-Bstatic -lpcre2-8 -Wl,-Bdynamic 2>/dev/null && rm testpcre testpcre.o && echo true||echo false)
+PCRE_CHECK = $(shell printf "\#define PCRE2_CODE_UNIT_WIDTH 8\\n\#include <pcre2.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpcre.o - 2>/dev/null && $(CC) -o testpcre testpcre.o $(LDFLAGS) -Wl,-Bstatic -lpcre2-8 -Wl,-Bdynamic 2>/dev/null && rm testpcre testpcre.o && echo true||echo false)
 ifeq ($(PCRE_CHECK), true)
     CFLAGS += -DWITH_PCRE
     PCRE_OBJS = pcre$(OBJSUFFICS)

Makefile.unix

@@ -54,14 +54,14 @@ ifeq ($(LIBSTATIC), true)
     STATIC_SUFFIX = -Wl,-Bdynamic
     ZLIB = -lz -lzstd
 endif
-WOLFSSL_CHECK ?= $(shell echo "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testwssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestwssl testwssl.o $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX) 2>/dev/null && rm testwssl testwssl.o && echo true||echo false)
+WOLFSSL_CHECK ?= $(shell printf "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testwssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestwssl testwssl.o $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX) 2>/dev/null && rm testwssl testwssl.o && echo true||echo false)
 ifeq ($(WOLFSSL_CHECK), true)
     LIBS += $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX)
     CFLAGS += -DWITH_SSL -DWITH_WOLFSSL
     SSL_OBJS = ssllib$(OBJSUFFICS) ssl$(OBJSUFFICS)
     ZLIB :=
 else
-OPENSSL_CHECK ?= $(shell echo "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestssl testssl.o $(STATIC_PREFIX) $(ZLIB) -lcrypto -lssl  $(STATIC_SUFFIX) 2>/dev/null && rm testssl testssl.o && echo true||echo false)
+OPENSSL_CHECK ?= $(shell printf "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testssl.o - 2>/dev/null && $(CC) $(LDFLAGS) -otestssl testssl.o $(STATIC_PREFIX) $(ZLIB) -lcrypto -lssl  $(STATIC_SUFFIX) 2>/dev/null && rm testssl testssl.o && echo true||echo false)
 ifeq ($(OPENSSL_CHECK), true)
     LIBS += $(STATIC_PREFIX) $(ZLIB) -lcrypto -lssl $(STATIC_SUFFIX)
     CFLAGS += -DWITH_SSL
@@ -70,13 +70,13 @@ else
     ZLIB :=
 endif
 endif
-PCRE_CHECK ?= $(shell echo "\#define PCRE2_CODE_UNIT_WIDTH 8\\n\#include <pcre2.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpcre.o - 2>/dev/null && $(CC) -o testpcre testpcre.o $(LDFLAGS) $(STATIC_PREFIX) -lpcre2-8 $(STATIC_SUFFIX) 2>/dev/null && rm testpcre testpcre.o && echo true||echo false)
+PCRE_CHECK ?= $(shell printf "\#define PCRE2_CODE_UNIT_WIDTH 8\\n\#include <pcre2.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpcre.o - 2>/dev/null && $(CC) -o testpcre testpcre.o $(LDFLAGS) $(STATIC_PREFIX) -lpcre2-8 $(STATIC_SUFFIX) 2>/dev/null && rm testpcre testpcre.o && echo true||echo false)
 ifeq ($(PCRE_CHECK), true)
     CFLAGS += -DWITH_PCRE
     PCRE_OBJS = pcre$(OBJSUFFICS)
     PCRE_LIBS = $(STATIC_PREFIX) -lpcre2-8 $(STATIC_SUFFIX)
 endif
-PAM_CHECK ?= $(shell echo "\#include <security/pam_appl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpam.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testpam testpam.o -lpam 2>/dev/null && rm testpam testpam.o && echo true||echo false)
+PAM_CHECK ?= $(shell printf "\#include <security/pam_appl.h>\\n int main(){return 0;}" | tr -d \\\\ | $(CC) -x c $(CFLAGS) -o testpam.o - 2>/dev/null && $(CC) $(LDFLAGS) -o testpam testpam.o -lpam 2>/dev/null && rm testpam testpam.o && echo true||echo false)
 ifeq ($(PAM_CHECK), true)
     PLUGINS += PamAuth
 endif

Makefile.win

@@ -47,14 +47,14 @@ ifeq ($(LIBSTATIC), true)
     STATIC_SUFFIX = -Wl,-Bdynamic
     ZLIB = -lz
 endif
-WOLFSSL_CHECK = $(shell echo "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d '\\\\' | $(CC) -x c $(CFLAGS) $(LDFLAGS) $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX) -o testwssl - 2>/dev/null && rm testwssl && echo true||echo false)
+WOLFSSL_CHECK = $(shell printf "\#include <wolfssl/options.h>\\n\#include <wolfssl/openssl/ssl.h>\\n int main(){return 0;}" | tr -d '\\\\' | $(CC) -x c $(CFLAGS) $(LDFLAGS) $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX) -o testwssl - 2>/dev/null && rm testwssl && echo true||echo false)
 ifeq ($(WOLFSSL_CHECK), true)
     LIBS += $(STATIC_PREFIX) -lwolfssl $(STATIC_SUFFIX) -lws2_32
     CFLAGS += -DWITH_SSL -DWITH_WOLFSSL
     SSL_OBJS = ssllib$(OBJSUFFICS) ssl$(OBJSUFFICS)
     ZLIB :=
 else
-OPENSSL_CHECK = $(shell echo "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d '\\\\' | $(CC) -x c $(CFLAGS) $(LDFLAGS) $(STATIC_PREFIX) $(ZLIB) -l crypto -l ssl $(STATIC_SUFFIX) -o testssl - 2>/dev/null && rm testssl && echo true||echo false)
+OPENSSL_CHECK = $(shell printf "\#include <openssl/ssl.h>\\n int main(){return 0;}" | tr -d '\\\\' | $(CC) -x c $(CFLAGS) $(LDFLAGS) $(STATIC_PREFIX) $(ZLIB) -l crypto -l ssl $(STATIC_SUFFIX) -o testssl - 2>/dev/null && rm testssl && echo true||echo false)
 ifeq ($(OPENSSL_CHECK), true)
     LIBS += $(STATIC_PREFIX) $(ZLIB) -l crypto -l ssl $(STATIC_SUFFIX) -lcrypt32
     CFLAGS += -DWITH_SSL
@@ -63,11 +63,11 @@ else
     ZLIB :=
 endif
 endif
-PAM_CHECK = $(shell echo "\#include <security/pam_appl.h>\\n int main(){return 0;}" | tr -d '\\\\' | $(CC) -x c $(CFLAGS) $(LDFLAGS) -l pam -o testpam - 2>/dev/null && rm testpam && echo true||echo false)
+PAM_CHECK = $(shell printf "\#include <security/pam_appl.h>\\n int main(){return 0;}" | tr -d '\\\\' | $(CC) -x c $(CFLAGS) $(LDFLAGS) -l pam -o testpam - 2>/dev/null && rm testpam && echo true||echo false)
 ifeq ($(PAM_CHECK), true)
     PLUGINS += PamAuth
 endif
-PCRE_CHECK = $(shell echo "\#define PCRE2_CODE_UNIT_WIDTH 8\\n#include <pcre2.h>\\n int main(){return 0;}" | tr -d '\\\\' | $(CC) -x c $(CFLAGS) $(LDFLAGS) $(STATIC_PREFIX) -lpcre2-8 $(STATIC_SUFFIX) -o testpcre - 2>/dev/null && rm testpcre && echo true||echo false)
+PCRE_CHECK = $(shell printf "\#define PCRE2_CODE_UNIT_WIDTH 8\\n#include <pcre2.h>\\n int main(){return 0;}" | tr -d '\\\\' | $(CC) -x c $(CFLAGS) $(LDFLAGS) $(STATIC_PREFIX) -lpcre2-8 $(STATIC_SUFFIX) -o testpcre - 2>/dev/null && rm testpcre && echo true||echo false)
 ifeq ($(PCRE_CHECK), true)
     CFLAGS += -DWITH_PCRE
     PCRE_OBJS = pcre$(OBJSUFFICS)