From 5d934b44b56fbf99c1c15bb72415d9fe81efc981 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Wed, 18 Dec 2019 21:23:16 -0800
Subject: configure: disable building as PIE.

On some GNU/Linux distributions, the compiler is configured
for PIE (position-independent executables).

This is horrible garbage which causes our "make tests" to run
more than 22% slower (e.g. 8.22 seconds versus 6.69) which is
unacceptable. Worse, this was implicated in a crash in TXR's
exception handling logic.  The committed workaround for that
problem stays in place for users who want to build TXR in the
PIE style anyway.

* configure: detect which, if any, of the known gcc and clang
options are available for disabling PIE and add those to
opt_flags (which turns into OPT_FLAGS in config.make).
---
 configure | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/configure b/configure
index 36e57b1e..c24b10ac 100755
--- a/configure
+++ b/configure
@@ -883,6 +883,31 @@ fi
 
 rm -f conftest$exe
 
+printf "Checking how to disable PIE ..."
+
+nopie_flags=
+
+for flag in -nopie -no-pie ; do
+  if conftest EXTRA_FLAGS=$flag ; then
+    nopie_flags=" $flag"
+    break
+  fi
+done
+
+for flag in -fnopie -fno-pie ; do
+  if conftest EXTRA_FLAGS=$flag ; then
+    nopie_flags="$nopie_flags $flag"
+    break
+  fi
+done
+
+if [ -n "$nopie_flags" ]; then
+  printf "%s\n" "$nopie_flags"
+  opt_flags="$opt_flags$nopie_flags"
+else
+  printf " n/a\n"
+fi
+
 #
 # Check for annoying clashes from non-conforming BSD-derived systems that don't
 # honor Unix/POSIX feature selection macros!
-- 
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