From ac77be992132bc074fabeda1e2b5259e6d64e7e0 Mon Sep 17 00:00:00 2001
From: oreo639 <oreo6391@gmail.com>
Date: Fri, 18 Apr 2025 14:32:32 -0700
Subject: [PATCH] mcpp: don't undefine libc feature macros

---
 .../mcpp/patches/libc-feature-macros.patch    | 59 +++++++++++++++++++
 srcpkgs/mcpp/template                         |  1 -
 2 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 srcpkgs/mcpp/patches/libc-feature-macros.patch

diff --git a/srcpkgs/mcpp/patches/libc-feature-macros.patch b/srcpkgs/mcpp/patches/libc-feature-macros.patch
new file mode 100644
index 00000000000..e6538e7955f
--- /dev/null
+++ b/srcpkgs/mcpp/patches/libc-feature-macros.patch
@@ -0,0 +1,59 @@
+Florian Weimer's c99 patch from https://sourceforge.net/p/mcpp/patches/7/
+
+Do not define and undefine _*_SOURCE macros.  These have special
+semantics to glibc.  <limits.h> may include <features.h>, and which
+point the feature configuration gets frozen.  Without this change,
+when system.c includes <unistd.h>, the feature macros are hard-coded
+as baseline POSIX, which does not include readlink.  This will lead to
+compilation errors with future compilers.
+
+diff --git a/src/configed.H b/src/configed.H
+index b4d1ebf3a6bfa280..bde16fc8db38a2c4 100644
+--- a/src/configed.H
++++ b/src/configed.H
+@@ -295,20 +295,7 @@
+  * ULONGMAX     should be defined to the ULONG_MAX in <limits.h>.
+  */
+ 
+-/* _POSIX_* only to get PATH_MAX    */
+-#define _POSIX_             1
+-#define _POSIX_SOURCE       1
+-#ifndef _POSIX_C_SOURCE
+-#define _POSIX_C_SOURCE     1
+-#define _POSIX_C_SOURCE_defined     1
+-#endif
+ #include    "limits.h"
+-#undef  _POSIX_
+-#undef  _POSIX_SOURCE
+-#ifdef  _POSIX_C_SOURCE_defined
+-#undef  _POSIX_C_SOURCE
+-#undef  _POSIX_C_SOURCE_defined
+-#endif
+ #define CHARBIT             CHAR_BIT
+ #define UCHARMAX            UCHAR_MAX
+ #define USHRTMAX            USHRT_MAX
+diff --git a/src/noconfig.H b/src/noconfig.H
+index 6b634fe0b32ff67c..7c923c900c8865dd 100644
+--- a/src/noconfig.H
++++ b/src/noconfig.H
+@@ -570,20 +570,7 @@
+ #include    "stdio.h"
+ 
+ /* PATHMAX is the maximum length of path-list on the host system.   */
+-/* _POSIX_* only to get PATH_MAX    */
+-#define _POSIX_             1
+-#define _POSIX_SOURCE       1
+-#ifndef _POSIX_C_SOURCE
+-#define _POSIX_C_SOURCE     1
+-#define _POSIX_C_SOURCE_defined     1
+-#endif
+ #include    "limits.h"
+-#undef  _POSIX_
+-#undef  _POSIX_SOURCE
+-#ifdef  _POSIX_C_SOURCE_defined
+-#undef  _POSIX_C_SOURCE
+-#undef  _POSIX_C_SOURCE_defined
+-#endif
+ #ifdef  PATH_MAX
+ #define PATHMAX     PATH_MAX        /* Posix macro  */
+ #else
diff --git a/srcpkgs/mcpp/template b/srcpkgs/mcpp/template
index f2820056917..397f35657fe 100644
--- a/srcpkgs/mcpp/template
+++ b/srcpkgs/mcpp/template
@@ -10,7 +10,6 @@ license="BSD-2-Clause"
 homepage="https://mcpp.sourceforge.net/"
 distfiles="${SOURCEFORGE_SITE}/mcpp/mcpp-${version}.tar.gz"
 checksum=3b9b4421888519876c4fc68ade324a3bbd81ceeb7092ecdbbc2055099fcb8864
-CFLAGS="-D_GNU_SOURCE" # readlink on glibc
 
 post_install() {
 	vlicense LICENSE