[gnome-sdk-images] Unset various env vars like CFLAGS during build

[Alexander Larsson <alexl src gnome org>]

commit ecf39981370fd078e3ca8124aa61fc8225bbb175
Author: Alexander Larsson <alexl redhat com>
Date:   Wed Mar 25 16:42:42 2015 +0100

    Unset various env vars like CFLAGS during build
    
    These can unexpectedly affect what flags rpm picks based on the
    outside environment.

 build.sh |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/build.sh b/build.sh
index 98b21b9..9769a80 100755
--- a/build.sh
+++ b/build.sh
@@ -11,6 +11,10 @@ LINUX_USER_CHROOT=`which linux-user-chroot 2> /dev/null`
 
 declare -x LC_ALL=en_US.utf8
 declare -x HOME=/self/packages
+unset CFLAGS
+unset CXXFLAGS
+unset LDFLAGS
+unset FFLAGS
 unset ACLOCAL_FLAGS
 unset ACLOCAL_PATH
 unset CPLUS_INCLUDE_PATH