even more improved way to find the necessary include path

ax_init_standard_project.m4

@@ -418,7 +418,15 @@ AC_DEFUN([AX_PKG_REQUIRE], [
     CPPFLAGS=${old_CPPFLAGS}
   fi
   if test ${$1_found} -eq 0; then
-    AC_MSG_ERROR([Feature $1 not found, need header $3 in module $2 $4])
+    if test -n "$3"; then
+      if test -n "$4"; then
+        AC_MSG_ERROR([Feature $1 not found, need header $3 in modules $2 or $4])
+      else
+        AC_MSG_ERROR([Feature $1 not found, need header $3 in module $2])
+      fi
+    else
+      AC_MSG_ERROR([Feature $1 not found please install module $2])
+    fi
   fi
   AM_CPPFLAGS+=" ${$1_CFLAGS}"
   AM_CXXFLAGS+=" ${$1_CFLAGS}"

configure.ac

@@ -41,7 +41,7 @@ CPPFLAGS="${CPPFLAGS} -DQT_NO_KEYWORDS"
 # libraries used
 AX_PKG_REQUIRE([pcsc], [libpcsclite], [pcsclite.h])
 AX_PKG_REQUIRE([ssl], [libssl], [openssl/crypto.h], [openssl])
-AX_PKG_REQUIRE([mrwcxx], [mrw-c++])
+AX_PKG_REQUIRE([mrwcxx], [mrw-c++], [mrw/checkcxx11.hxx])
 AX_PKG_REQUIRE([pkcs11], [p11-kit-1], [pkcs11.h], [libpkcs11-helper-1])
 
 # create output