[FFmpeg-cvslog] configure: Force mingw's ld to keep the reloc section

[Alex Smith]

ffmpeg | branch: master | Alex Smith <alex.smith at warpsharp.info> | Mon Sep 21 00:41:36 2015 -0400| [91b668acd6decec0a6f8d20bf56e2644f96adcb9] | committer: Michael Niedermayer

configure: Force mingw's ld to keep the reloc section

Binutils will always strip the relocation information from executable
files even if it needs it (dynamicbase/ASLR).  We can work around this
by using the pic-executable flag combined with setting the correct entry
point since apparently ld forgets what that should be.  This problem
affects both 32 and 64-bit mingw-w64.

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=91b668acd6decec0a6f8d20bf56e2644f96adcb9
---

 configure |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/configure b/configure
index da9f42e..f6bc622 100755
--- a/configure
+++ b/configure
@@ -4392,6 +4392,16 @@ case $target_os in
         objformat="win32"
         ranlib=:
         enable dos_paths
+        # Lets work around some stupidity in binutils.
+        # ld will strip relocations from executables even though we need them
+        # for dynamicbase (ASLR).  Using -pie does retain the reloc section
+        # however ld then forgets what the entry point should be (oops) so we
+        # have to manually (re)set it.
+        if enabled x86_32; then
+            add_ldexeflags -Wl,--pic-executable,-e,_mainCRTStartup
+        elif enabled x86_64; then
+            add_ldexeflags -Wl,--pic-executable,-e,mainCRTStartup
+        fi
         ;;
     win32|win64)
         disable symver