Use PKG_CONFIG_PATH along with PKG_CHECK_MODULES in openssl.m4 and libz.m4.

Replaced LIBZ_LIB and LIBZ_CPPFLAGS with ZLIB_LIB and ZLIB_CFLAGS
respectively.

configure.ac

@@ -144,8 +144,8 @@ fi
 if test "x$with_libz" = "xyes"; then
   AM_PATH_LIBZ
   if test "x$have_libz" = "xyes"; then
-    LIBS="$LIBZ_LIBS $LIBS"
-    CPPFLAGS="$LIBZ_CPPFLAGS $CPPFLAGS"
+    LIBS="$ZLIB_LIBS $LIBS"
+    CPPFLAGS="$ZLIB_CFLAGS $CPPFLAGS"
   elif test "x$with_libz_requested" = "xyes"; then
     ARIA2_DEP_NOT_MET([libz])
   fi

m4/libz.m4

@@ -9,25 +9,32 @@ if test "x$libz_prefix" = "x"; then
   libz_prefix="/usr"
 fi
 
-libz_prefix_lib=$libz_prefix/lib
-libz_prefix_include=$libz_prefix/include
-
 LIBS_save=$LIBS
 CPPFLAGS_save=$CPPFLAGS
+PKG_CONFIG_PATH_save=$PKG_CONFIG_PATH
+
+PKG_CONFIG_PATH="$libz_prefix/lib/pkgconfig:$PKG_CONFIG_PATH"
+PKG_CHECK_MODULES([ZLIB], [zlib >= 1.2.3], [have_libz=yes], [have_libz=no])
+
+if test "x$have_libz" != "xyes"; then
+  libz_prefix_lib=$libz_prefix/lib
+  libz_prefix_include=$libz_prefix/include
 
-LIBS="-L$libz_prefix_lib $LIBS"
-CPPFLAGS="-I$libz_prefix_include $CPPFLAGS"
+  LIBS="-L$libz_prefix_lib $LIBS"
+  CPPFLAGS="-I$libz_prefix_include $CPPFLAGS"
+
+  AC_CHECK_LIB([z], [zlibVersion], [have_libz=yes])
+  if test "x$have_libz" = "xyes"; then
+    ZLIB_LIBS="-L$libz_prefix_lib -lz"
+    ZLIB_CFLAGS="-I$libz_prefix_include"
+  fi
+fi
 
-AC_CHECK_LIB([z], [zlibVersion], [have_libz=yes])
 if test "x$have_libz" = "xyes"; then
-    AC_DEFINE([HAVE_LIBZ], [1], [Define to 1 if you have libz.])
-    LIBZ_LIBS="-L$libz_prefix_lib -lz"
-    LIBZ_CPPFLAGS="-I$libz_prefix_include"
-    AC_SUBST(LIBZ_LIBS)
-    AC_SUBST(LIBZ_CPPFLAGS)
+  AC_DEFINE([HAVE_LIBZ], [1], [Define to 1 if you have libz.])
 fi
 
 LIBS=$LIBS_save
 CPPFLAGS=$CPPFLAGS_save
-
+PKG_CONFIG_PATH=$PKG_CONFIG_PATH_save
 ])

m4/openssl.m4

@@ -11,24 +11,12 @@ fi
 
 LIBS_save=$LIBS
 CPPFLAGS_save=$CPPFLAGS
+PKG_CONFIG_PATH_save=$PKG_CONFIG_PATH
 
-PKG_CONFIG="$openssl_prefix/bin/pkg-config"
-if test -x $PKG_CONFIG; then
-  AC_MSG_CHECKING([checking availability of openssl using pkg-config])
-  $PKG_CONFIG --exists openssl
-  if test "$?" = "0"; then
-    # Use pkg-config to detect LIBS and CFLAGS
-    OPENSSL_LIBS=`$PKG_CONFIG --libs openssl`
-    OPENSSL_CFLAGS=`$PKG_CONFIG --cflags openssl`
+PKG_CONFIG_PATH="$openssl_prefix/lib/pkgconfig:$PKG_CONFIG_PATH"
+PKG_CHECK_MODULES([OPENSSL], [openssl >= 0.9.8],
+                  [have_openssl=yes], [have_openssl=no])
 
-    LIBS="$OPENSSL_LIBS $LIBS"
-    CPPFLAGS="$OPENSSL_CFLAGS $CPPFLAGS"
-    have_openssl=yes
-    AC_MSG_RESULT([yes])
-  else
-    AC_MSG_RESULT([no])
-  fi
-fi
 if test "x$have_openssl" != "xyes"; then
   openssl_prefix_lib=$openssl_prefix/lib
   openssl_prefix_include=$openssl_prefix/include
@@ -40,7 +28,8 @@ if test "x$have_openssl" != "xyes"; then
   AC_CHECK_LIB([crypto], [main], [have_openssl=yes; LIBS="-lcrypto $LIBS"])
   if test "x$have_openssl" = "xyes"; then
     have_openssl=no
-    AC_CHECK_LIB([ssl], [SSL_library_init], [have_openssl=yes LIBS="-lssl $LIBS"])
+    AC_CHECK_LIB([ssl], [SSL_library_init],
+                 [have_openssl=yes LIBS="-lssl $LIBS"])
     if test "x$have_openssl" = "xyes"; then
       OPENSSL_LIBS="-L$openssl_prefix_lib -lssl -lcrypto"
       OPENSSL_CFLAGS="-I$openssl_prefix_include"
@@ -50,13 +39,13 @@ fi
 
 if test "x$have_openssl" = "xyes"; then
   AC_DEFINE([HAVE_LIBSSL], [1], [Define to 1 if you have openssl.])
+  LIBS="$OPENSSL_LIBS $LIBS"
+  CPPFLAGS="$OPENSSL_CFLAGS $CPPFLAGS"
   # check whether EVP_DigestInit_ex exists. Old openssl doesn't have it.
   AC_CHECK_FUNCS([EVP_DigestInit_ex], [have_digestinit_ex=yes])
   if test "x$have_digestinit_ex" = "x"; then
     AC_DEFINE([HAVE_OLD_LIBSSL], [1], [Define to 1 if you have old openssl.])
   fi
-  AC_SUBST(OPENSSL_LIBS)
-  AC_SUBST(OPENSSL_CFLAGS)
   # search for sha224 support
   AC_CHECK_FUNCS([EVP_sha224])
   # search for sha256 support
@@ -69,4 +58,5 @@ fi
 
 LIBS=$LIBS_save
 CPPFLAGS=$CPPFLAGS_save
+PKG_CONFIG_PATH=$PKG_CONFIG_PATH_save
 ])