fixup! release: add Mac OSX installer build

Starting with upstream commit 4580bcd ("osxkeychain: avoid
incorrectly skipping store operation", 2025-11-14), the osxkeychain
credential helper includes git-compat-util.h. That header includes
openssl/ssl.h unless -DNO_OPENSSL is defined:

    ../../../git-compat-util.h:199:10: fatal error:
        'openssl/ssl.h' file not found

On macOS, the main Makefile sets NO_OPENSSL (because Apple Common
Crypto is used instead) and adds -DNO_OPENSSL to BASIC_CFLAGS. But
contrib Makefiles that only include config.mak* files don't get this
logic - they only see the variables, not the Makefile rules that
convert NO_OPENSSL into -DNO_OPENSSL.

Add -DNO_OPENSSL to BASIC_CFLAGS in config.mak so that contrib builds
like osxkeychain can pick it up.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>

Author: dscho

.github/workflows/build-git-installers.yml

@@ -491,6 +491,11 @@ jobs:
           HOST_CPU = universal
           BASIC_CFLAGS += -arch arm64 -arch x86_64
 
+          # macOS uses Apple Common Crypto instead of OpenSSL. The main Makefile
+          # sets NO_OPENSSL and adds -DNO_OPENSSL to BASIC_CFLAGS, but contrib
+          # Makefiles that only include config.mak* don't get this logic.
+          BASIC_CFLAGS += -DNO_OPENSSL
+
           # CRITICAL FIX: Disable USE_HOMEBREW_LIBICONV
           # On Darwin 24+ (macOS 15), config.mak.uname sets USE_HOMEBREW_LIBICONV
           # which causes ICONVDIR to point to Homebrew's libiconv. But Homebrew's