diff --git a/system/efitools/efitools.SlackBuild b/system/efitools/efitools.SlackBuild
index ced522780f..771568ec1e 100644
--- a/system/efitools/efitools.SlackBuild
+++ b/system/efitools/efitools.SlackBuild
@@ -45,14 +45,21 @@ OUTPUT=${OUTPUT:-/tmp}
 
 # It's not safe to specify build flags since some EFI programs are built.
 if [ "$ARCH" = "i486" ]; then
+  SLKCFLAGS="-O2 -march=i486 -mtune=i686"
   LIBDIRSUFFIX=""
   EFI_ARCH=ia32
 elif [ "$ARCH" = "i686" ]; then
+  SLKCFLAGS="-O2 -march=i686 -mtune=i686"
   LIBDIRSUFFIX=""
   EFI_ARCH=ia32
 elif [ "$ARCH" = "x86_64" ]; then
+  SLKCFLAGS="-O2 -fPIC"
   LIBDIRSUFFIX="64"
   EFI_ARCH=x86_64
+else
+  SLKCFLAGS="-O2"
+  LIBDIRSUFFIX=""
+  EFI_ARCH="$ARCH"
 fi
 
 set -e
@@ -84,7 +91,13 @@ find -L . \
  \( -perm 666 -o -perm 664 -o -perm 640 -o -perm 600 -o -perm 444 \
   -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;
 
-make CRTPATH=/usr/lib${LIBDIRSUFFIX}/gnuefi MYGUID=${MYGUID} ARCH=$EFI_ARCH
+unset ARCH
+
+make \
+  CRTPATH=/usr/lib${LIBDIRSUFFIX}/gnuefi \
+  MYGUID=${MYGUID} \
+  ARCH=$EFI_ARCH \
+  CFLAGS="-std=gnu89 $SLKCFLAGS"
 make install DESTDIR=$PKG MANDIR=$PKG/usr/man/man1 ARCH=$EFI_ARCH
 
 # Delete the private keys in $TMP. Especially important if the user doesn't