[Tarantool-patches] [PATCH decNumber 1/1] Fix build on Mac with gcc and XCode 11

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

There is a bug in XCode 11 which makes some standard C headers
not self sufficient. At least <stdlib.h> and <algorithm> are
affected. When they are included first, compilation fails with
creepy errors like this:

    In file included
    from /Applications/Xcode.app/Contents/Developer/
        Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/
        sys/wait.h:110,
    from /Applications/Xcode.app/Contents/Developer/
        Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/
        stdlib.h:66,
    from /Users/gerold/Work/Repositories/tarantool/third_party/
        zstd/lib/common/zstd_common.c:16:
        /Applications/Xcode.app/Content/Developer/
        Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/
        sys/resource.h:
    In function 'getiopolicy_np': /Applications/Xcode.app/Contents/Developer/
        Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/
        sys/resource.h:447:34: error:
            expected declaration specifiers before '__OSX_AVAILABLE_STARTING'
            447 | int     getiopolicy_np(int, int)
            __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

The patch workarounds the bug by changing header include order.
Part of https://github.com/tarantool/tarantool/issues/4580
---
Issue: https://github.com/tarantool/tarantool/issues/4580
Branch: https://github.com/tarantool/decNumber/tree/gerold103/mac-build-gcc

Note, the branch depends on another branch in decNumber
repository. decNumber should be pushed first, then this branch
should be updated to look at the newest decNumber.

Discussion of the same issue from which I took the workaround:
https://github.com/Homebrew/homebrew-core/issues/44579

 decNumber.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/decNumber.c b/decNumber.c
index e8947fe..85deb13 100644
--- a/decNumber.c
+++ b/decNumber.c
@@ -162,9 +162,9 @@
 /*      **  -- raise to the power                                     */
 /* ------------------------------------------------------------------ */
 
+#include <string.h>                // for strcpy
 #include <stdlib.h>                // for malloc, free, etc.
 #include <stdio.h>                 // for printf [if needed]
-#include <string.h>                // for strcpy
 #include <ctype.h>                 // for lower
 #include "decNumber.h"             // base number library
 #include "decNumberLocal.h"        // decNumber local types, etc.
-- 
2.21.0 (Apple Git-122.2)