From deb7bf35b71566636029b35c4a17cb8fd4d241a1 Mon Sep 17 00:00:00 2001
From: James R <justsomejames2@gmail.com>
Date: Wed, 17 Jun 2020 22:49:12 -0700
Subject: [PATCH] Detect the compiler version and set the correct GCC flag

If the version is not supported by the Makefile, the flag for the latest
version supported is set instead.

(cherry picked from commit bf90fbb91f28af30ff79523681e7f73e60121535)
---
 src/Makefile.cfg | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/src/Makefile.cfg b/src/Makefile.cfg
index a3baeedd..7a0455aa 100644
--- a/src/Makefile.cfg
+++ b/src/Makefile.cfg
@@ -1,3 +1,4 @@
+# vim: ft=make
 #
 # Makefile.cfg for SRB2
 #
@@ -7,6 +8,42 @@
 # and other things
 #
 
+# See the following variable don't start with 'GCC'. This is
+# to avoid a false positive with the version detection...
+
+SUPPORTED_GCC_VERSIONS:=\
+	91\
+	81 82 83\
+	71 72\
+	61 62 63 64\
+	51 52 53 54\
+	40 41 42 43 44 45 46 47 48 49
+
+LATEST_GCC_VERSION=9.1
+
+# Automatically set version flag, but not if one was manually set
+ifeq   (,$(filter GCC%,$(.VARIABLES)))
+ ifneq (,$(findstring GCC,$(shell $(CC) --version))) # if it's GCC
+  version:=$(shell $(CC) -dumpversion)
+
+  # Turn version into words of major, minor
+  v:=$(subst ., ,$(version))
+  # concat. major minor
+  v:=$(word 1,$(v))$(word 2,$(v))
+
+  # If this version is not in the list, default to the latest supported
+  ifeq (,$(filter $(v),$(SUPPORTED_GCC_VERSIONS)))
+   $(info\
+		Your compiler version, GCC $(version) is not supported by the Makefile.\
+		The Makefile will assume GCC $(LATEST_GCC_VERSION).)
+   GCC$(subst .,,$(LATEST_GCC_VERSION))=1
+  else
+   $(info Detected GCC $(version) (GCC$(v)))
+   GCC$(v)=1
+  endif
+ endif
+endif
+
 ifdef GCC91
 GCC83=1
 endif