desktop/afterstep: Fixed build with gcc-5.2.0.

Signed-off-by: David Spencer <baildon.research@googlemail.com>

desktop/afterstep/afterstep.SlackBuild

@@ -73,8 +73,8 @@ 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 {} \;
 
-CFLAGS="$SLKCFLAGS -std=gnu89" \
-CXXFLAGS="$SLKCFLAGS -std=gnu89" \
+CFLAGS="$SLKCFLAGS -fgnu89-inline" \
+CXXFLAGS="$SLKCFLAGS" \
 ./configure \
   --prefix=/usr \
   --libdir=/usr/lib${LIBDIRSUFFIX} \
@@ -87,7 +87,7 @@ CXXFLAGS="$SLKCFLAGS -std=gnu89" \
   --with-imageloader="" \
   --build=$ARCH-slackware-linux
 
-make
+make -j1
 make install DESTDIR=$PKG
 
 find $PKG -print0 | xargs -0 file | grep -e "executable" -e "shared object" | grep ELF \