Fixing autoconf/autoheader usage

Enabling autoheader to actually work and adding initial check function
structure for detecting whether we're on z/OS with GSKSSL or on a system
which has OpenSSL.

ax_check_gskssl.m4

@@ -0,0 +1,88 @@
+AU_ALIAS([CHECK_SSL], [AX_CHECK_GSKSSL])
+AC_DEFUN([AX_CHECK_GSKSSL], [
+    found=false
+    AC_ARG_WITH(gskssl,
+        AS_HELP_STRING([--with-gskssl=DIR],
+            [root of the OpenSSL directory]),
+        [
+            case "$withval" in
+            "" | y | ye | yes | n | no)
+            AC_MSG_ERROR([Invalid --with-gskssl value])
+              ;;
+            *) ssldirs="$withval"
+              ;;
+            esac
+        ], [
+            # if pkg-config is installed and gskssl has installed a .pc file,
+            # then use that information and don't search ssldirs
+            AC_PATH_PROG(PKG_CONFIG, pkg-config)
+            if test x"$PKG_CONFIG" != x""; then
+                GSKSSL_LDFLAGS=`$PKG_CONFIG gskssl --libs-only-L 2>/dev/null`
+                if test $? = 0; then
+                    GSKSSL_LIBS=`$PKG_CONFIG gskssl --libs-only-l 2>/dev/null`
+                    GSKSSL_INCLUDES=`$PKG_CONFIG gskssl --cflags-only-I 2>/dev/null`
+                    found=true
+                fi
+            fi
+
+            # no such luck; use some default ssldirs
+            if ! $found; then
+                ssldirs="/usr/local/ssl /usr/lib/ssl /usr/ssl /usr/pkg /usr/local /usr"
+            fi
+        ]
+        )
+
+
+    # note that we #include <gskssl/foo.h>, so the OpenSSL headers have to be in
+    # an 'gskssl' subdirectory
+
+    if ! $found; then
+        GSKSSL_INCLUDES=
+        for ssldir in $ssldirs; do
+            AC_MSG_CHECKING([for gskssl/ssl.h in $ssldir])
+            if test -f "$ssldir/include/gskssl/ssl.h"; then
+                GSKSSL_INCLUDES="-I$ssldir/include"
+                GSKSSL_LDFLAGS="-L$ssldir/lib"
+                GSKSSL_LIBS="-lssl -lcrypto"
+                found=true
+                AC_MSG_RESULT([yes])
+                break
+            else
+                AC_MSG_RESULT([no])
+            fi
+        done
+
+        # if the file wasn't found, well, go ahead and try the link anyway -- maybe
+        # it will just work!
+    fi
+
+    # try the preprocessor and linker with our new flags,
+    # being careful not to pollute the global LIBS, LDFLAGS, and CPPFLAGS
+
+    AC_MSG_CHECKING([whether compiling and linking against OpenSSL works])
+    echo "Trying link with GSKSSL_LDFLAGS=$GSKSSL_LDFLAGS;" \
+        "GSKSSL_LIBS=$GSKSSL_LIBS; GSKSSL_INCLUDES=$GSKSSL_INCLUDES" >&AS_MESSAGE_LOG_FD
+
+    save_LIBS="$LIBS"
+    save_LDFLAGS="$LDFLAGS"
+    save_CPPFLAGS="$CPPFLAGS"
+    LDFLAGS="$LDFLAGS $GSKSSL_LDFLAGS"
+    LIBS="$GSKSSL_LIBS $LIBS"
+    CPPFLAGS="$GSKSSL_INCLUDES $CPPFLAGS"
+    AC_LINK_IFELSE(
+        AC_LANG_PROGRAM([#include <gskssl/ssl.h>], [SSL_new(NULL)]),
+        [
+            AC_MSG_RESULT([yes])
+            $1
+        ], [
+            AC_MSG_RESULT([no])
+            $2
+        ])
+    CPPFLAGS="$save_CPPFLAGS"
+    LDFLAGS="$save_LDFLAGS"
+    LIBS="$save_LIBS"
+
+    AC_SUBST([GSKSSL_INCLUDES])
+    AC_SUBST([GSKSSL_LIBS])
+    AC_SUBST([GSKSSL_LDFLAGS])
+])

configure.ac

@@ -10,7 +10,7 @@ AS_SHELL_SANITIZE
 
 AC_CONFIG_SRCDIR([src/netpgp.c])
 AC_CONFIG_AUX_DIR([buildaux])
-AC_CONFIG_HEADER([src/config.h])
+AC_CONFIG_HEADER([include/netpgp/config.h])
 
 AM_INIT_AUTOMAKE([-Wall foreign])
 AM_MAINTAINER_MODE
@@ -75,9 +75,10 @@ AC_TYPE_UINT8_T
 
 # check for openssl
 m4_include([ax_check_openssl.m4])
+m4_include([ax_check_gskssl.m4])
 
-AX_CHECK_OPENSSL([LIBS="$LIBS $OPENSSL_LDFLAGS $OPENSSL_LIBS" INCLUDES="$INCLUDES $OPENSSL_INCLUDES"],
-	[AC_MSG_ERROR([Missing OpenSSL])])
+AX_CHECK_OPENSSL([LIBS="$LIBS $OPENSSL_LDFLAGS $OPENSSL_LIBS" INCLUDES="$INCLUDES $OPENSSL_INCLUDES"])
+AX_CHECK_GSKSSL([LIBS="$LIBS $OPENSSL_LDFLAGS $OPENSSL_LIBS" INCLUDES="$INCLUDES $OPENSSL_INCLUDES"])
 
 CPPFLAGS="$CPPFLAGS $INCLUDES"