toolchain: gdb: fix build error with Xcode 16.3

Xcode 16.3 defines TARGET_OS_MAC, it was not defined in prior versions.
zutil.h conditionally defines fdopen as NULL when this macro is defined,
resulting in the following build error:

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_stdio.h:318:7: error: expected identifier or '('
  318 | FILE    *fdopen(int, const char *) __DARWIN_ALIAS_STARTING(__MAC_10_6, __IPHONE_2_0, __DARWIN_ALIAS(fdopen));
      |          ^
./zutil.h:147:33: note: expanded from macro 'fdopen'
  147 | #        define fdopen(fd,mode) NULL /* No fdopen() */

In Xcode 16.2 and earlier, TARGET_OS_MAC was not defined so this entire
block was ignored, gcc and gdb used to compile and work fine.

This may have been used for compatibility with older versions of macOS,
but is no longer needed. By pure luck, the build worked fine for a long
time, because it did not properly detect macOS.
Fixed by removing the check for TARGET_OS_MAC.

Note that since Xcode 16.3, an entire set of TARGET_OS macros
are now defined, most of which are set to 0:
TARGET_OS_LINUX 0
TARGET_OS_MAC 1
TARGET_OS_OSX 1

Signed-off-by: Georgi Valkov <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/18467
(cherry picked from commit dfb8115d0cc00d40f2884d3119b44f3da69c997a)
Link: https://github.com/openwrt/openwrt/pull/19096
Signed-off-by: Robert Marko <[email protected]>

toolchain/gdb/Makefile

@@ -8,7 +8,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=gdb
 PKG_VERSION:=15.2
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@GNU/gdb

toolchain/gdb/patches/130-fix-build-error-with-Xcode-16.3.patch

@@ -0,0 +1,52 @@
+From 0a084bb6c04e453183530c3e20727be1cc55ff9a Mon Sep 17 00:00:00 2001
+From: Georgi Valkov <[email protected]>
+Date: Mon, 14 Apr 2025 15:18:00 +0300
+Subject: [PATCH] zlib: fix build error with Xcode 16.3
+
+Xcode 16.3 defines TARGET_OS_MAC, it was not defined in prior versions.
+zutil.h conditionally defines fdopen as NULL when this macro is defined,
+resulting in the following build error:
+
+/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_stdio.h:318:7: error: expected identifier or '('
+  318 | FILE    *fdopen(int, const char *) __DARWIN_ALIAS_STARTING(__MAC_10_6, __IPHONE_2_0, __DARWIN_ALIAS(fdopen));
+      |          ^
+./zutil.h:147:33: note: expanded from macro 'fdopen'
+  147 | #        define fdopen(fd,mode) NULL /* No fdopen() */
+
+In Xcode 16.2 and earlier, TARGET_OS_MAC was not defined so this entire
+block was ignored, gcc and gdb used to compile and work fine.
+
+This may have been used for compatibility with older versions of macOS,
+but is no longer needed. By pure luck, the build worked fine for a long
+time, because it did not properly detect macOS.
+Fixed by removing the check for TARGET_OS_MAC.
+
+Note that since Xcode 16.3, an entire set of TARGET_OS macros
+are now defined, most of which are set to 0:
+TARGET_OS_LINUX 0
+TARGET_OS_MAC 1
+TARGET_OS_OSX 1
+
+[1] https://github.com/openwrt/openwrt/pull/18467
+
+Signed-off-by: Georgi Valkov <[email protected]>
+---
+ zlib/zutil.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/zlib/zutil.h b/zlib/zutil.h
+index d9a20ae1bf4..183e51b96b6 100644
+--- a/zlib/zutil.h
++++ b/zlib/zutil.h
+@@ -137,7 +137,7 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
+ #  endif
+ #endif
+ 
+-#if defined(MACOS) || defined(TARGET_OS_MAC)
++#if defined(MACOS)
+ #  define OS_CODE  7
+ #  ifndef Z_SOLO
+ #    if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
+-- 
+2.49.0
+