[4/6] Fix configure file

Source: https://github.com/madler/zlib/pull/607

zlib-1.2.12-fix-configure.patch

@@ -0,0 +1,46 @@
+From a6cd9e1230acdb535bd57bbc350020da3d24eaf3 Mon Sep 17 00:00:00 2001
+From: Sam James <sam@gentoo.org>
+Date: Mon, 28 Mar 2022 08:40:45 +0100
+Subject: [PATCH] Fix CC logic in configure
+
+In https://github.com/madler/zlib/commit/e9a52aa129efe3834383e415580716a7c4027f8d,
+the logic was changed to try check harder for GCC, but it dropped
+the default setting of cc=${CC}. It was throwing away any pre-set CC value as
+a result.
+
+The rest of the script then cascades down a bad path because it's convinced
+it's not GCC or a GCC-like compiler.
+
+This led to e.g. misdetection of inability to build shared libs
+for say, multilib cases (w/ CC being one thing from the environment being used
+for one test (e.g. x86_64-unknown-linux-gnu-gcc -m32 and then 'cc' used for
+shared libs (but missing "-m32"!)). Obviously just one example of how
+the old logic could break.
+
+This restores the old default of 'CC' if nothing overrides it later
+in configure.
+
+Bug: https://bugs.gentoo.org/836308
+Signed-off-by: Sam James <sam@gentoo.org>
+---
+ configure | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/configure b/configure
+index a21be36..cdf0e5b 100755
+--- a/configure
++++ b/configure
+@@ -185,7 +185,10 @@ if test -z "$CC"; then
+   else
+     cc=${CROSS_PREFIX}cc
+   fi
++else
++  cc=${CC}
+ fi
++
+ cflags=${CFLAGS-"-O3"}
+ # to force the asm version use: CFLAGS="-O3 -DASMV" ./configure
+ case "$cc" in
+-- 
+2.34.3
+