From 04615263c73a6db44daa2e39ae20c95d5311b9c2 Mon Sep 17 00:00:00 2001
From: Ben Gamari <ben@smart-cactus.org>
Date: Tue, 24 Sep 2019 18:39:23 -0400
Subject: configure: Drop GccLT46

GCC 4.6 was released 7 years ago. I think we can finally assume that
it's available. This is a simplification prompted by #15742.
---
 aclocal.m4      | 7 ++-----
 mk/config.mk.in | 1 -
 mk/warnings.mk  | 2 --
 rts/ghc.mk      | 3 ---
 4 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/aclocal.m4 b/aclocal.m4
index b6e72cc4ad..aea0d64886 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1322,18 +1322,15 @@ AC_DEFUN([FP_GCC_VERSION], [
   then
     AC_MSG_ERROR([gcc is required])
   fi
-  GccLT46=NO
   AC_CACHE_CHECK([version of gcc], [fp_cv_gcc_version],
   [
       # Be sure only to look at the first occurrence of the "version " string;
       # Some Apple compilers emit multiple messages containing this string.
       fp_cv_gcc_version="`$CC -v 2>&1 | sed -n -e '1,/version /s/.*version [[^0-9]]*\([[0-9.]]*\).*/\1/p'`"
-      FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-lt], [4.4],
-                          [AC_MSG_ERROR([Need at least gcc version 4.4 (4.7+ recommended)])])
-      FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-lt], [4.6], GccLT46=YES)
+      FP_COMPARE_VERSIONS([$fp_cv_gcc_version], [-lt], [4.6],
+                          [AC_MSG_ERROR([Need at least gcc version 4.6 (4.7+ recommended)])])
   ])
   AC_SUBST([GccVersion], [$fp_cv_gcc_version])
-  AC_SUBST(GccLT46)
 ])# FP_GCC_VERSION
 
 dnl Check to see if the C compiler is clang or llvm-gcc
diff --git a/mk/config.mk.in b/mk/config.mk.in
index 05ad6ad199..cd85c65189 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -526,7 +526,6 @@ GccVersion            = @GccVersion@
 # TargetPlatformFull retains the string passed to configure so we have it in
 # the necessary format to pass to libffi's configure.
 TargetPlatformFull    = @TargetPlatformFull@
-GccLT46         = @GccLT46@
 
 # Do we have a C compiler using an LLVM back end?
 CcLlvmBackend   = @CcLlvmBackend@
diff --git a/mk/warnings.mk b/mk/warnings.mk
index cee408d061..e2116a332a 100644
--- a/mk/warnings.mk
+++ b/mk/warnings.mk
@@ -21,12 +21,10 @@ ifneq "$(CcLlvmBackend)" "YES"
 
 # Debian doesn't turn -Werror=unused-but-set-variable on by default, so
 # we turn it on explicitly for consistency with other users
-ifeq "$(GccLT46)" "NO"
 # Never set the flag on Windows as the host gcc may be too old.
 ifneq "$(HostOS_CPP)" "mingw32"
 SRC_CC_WARNING_OPTS += -Werror=unused-but-set-variable
 endif
-endif
 
 # Suppress the warning about __sync_fetch_and_nand (#9678).
 libraries/ghc-prim/cbits/atomic_CC_OPTS += -Wno-sync-nand
diff --git a/rts/ghc.mk b/rts/ghc.mk
index 59d5994147..25a1561814 100644
--- a/rts/ghc.mk
+++ b/rts/ghc.mk
@@ -337,9 +337,6 @@ WARNING_OPTS += -Wpointer-arith
 WARNING_OPTS += -Wmissing-noreturn
 WARNING_OPTS += -Wnested-externs
 WARNING_OPTS += -Wredundant-decls
-ifeq "$(GccLT46)" "NO"
-WARNING_OPTS += -Wundef
-endif
 # Some gccs annoyingly enable this archaic specimen by default
 WARNING_OPTS += -Wno-aggregate-return
 
-- 
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