configure: fix --with-zlib when a path is specified

Prior to this change if you attempted to configure curl using
--wtih-zlib and specified a path the path would be ignored if you also
had pkg-config installed on your system.  This situation can easily
arise when you are cross compiling.  This change moves the test for
detecting zlib settings via pkg-config only if OPT_ZLIB is not set.

Closes https://github.com/curl/curl/pull/1292

diff --git a/configure.ac b/configure.ac
index 5c77b0f4c8f50cf6af57410a81e0363d7000d1f3..abd0def36990406fe701869fda8354a9ad8dc2ca 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -893,17 +893,16 @@ else
     OPT_ZLIB=""
   fi
 
-  CURL_CHECK_PKGCONFIG(zlib)
-
-  if test "$PKGCONFIG" != "no" ; then
-    LIBS="`$PKGCONFIG --libs-only-l zlib` $LIBS"
-    LDFLAGS="`$PKGCONFIG --libs-only-L zlib` $LDFLAGS"
-    CPPFLAGS="`$PKGCONFIG --cflags-only-I zlib` $CPPFLAGS"
-    OPT_ZLIB=""
-    HAVE_LIBZ="1"
-  fi
-
   if test -z "$OPT_ZLIB" ; then
+    CURL_CHECK_PKGCONFIG(zlib)
+
+    if test "$PKGCONFIG" != "no" ; then
+      LIBS="`$PKGCONFIG --libs-only-l zlib` $LIBS"
+      LDFLAGS="`$PKGCONFIG --libs-only-L zlib` $LDFLAGS"
+      CPPFLAGS="`$PKGCONFIG --cflags-only-I zlib` $CPPFLAGS"
+      OPT_ZLIB=""
+      HAVE_LIBZ="1"
+    fi
 
     if test -z "$HAVE_LIBZ"; then