package/git-crypt: fix build with openssl 3.x

Fix was proposed upstream: https://github.com/AGWA/git-crypt/issues/290

Alpine Linux uses a similar fix:
https://git.alpinelinux.org/aports/commit/community/git-crypt/APKBUILD?id=25b42ad7711b08c63aaf3c24af80a4bcd7607817

Fixes:
http://autobuild.buildroot.net/results/dfb/dfb5da218bb323edc57cc609c2b75d5fbc6e1fd1/

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/git-crypt/git-crypt.mk

@@ -15,7 +15,8 @@ GIT_CRYPT_LIBS = `$(PKG_CONFIG_HOST_BINARY) --libs openssl`
 define GIT_CRYPT_BUILD_CMDS
 	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) $(TARGET_CONFIGURE_OPTS) \
 		LDFLAGS="$(TARGET_LDFLAGS) $(GIT_CRYPT_LIBS)" \
-		CXXFLAGS="$(TARGET_CXXFLAGS) -std=c++11" PREFIX=/usr
+		CXXFLAGS="$(TARGET_CXXFLAGS) -std=c++11 -DOPENSSL_API_COMPAT=0x30000000L" \
+		PREFIX=/usr
 endef
 
 define GIT_CRYPT_INSTALL_TARGET_CMDS