Index: head/Makefile.inc1
===================================================================
--- head/Makefile.inc1
+++ head/Makefile.inc1
@@ -750,19 +750,6 @@
 .endif
 .if ${WANT_COMPILER_TYPE} == gcc || \
     (defined(X_COMPILER_TYPE) && ${X_COMPILER_TYPE} == gcc)
-# GCC requires -isystem and -L when using a cross-compiler.  --sysroot
-# won't set header path and -L is used to ensure the base library path
-# is added before the port PREFIX library path.
-XCFLAGS+=	-isystem ${WORLDTMP}/usr/include -L${WORLDTMP}/usr/lib
-# GCC requires -B to find /usr/lib/crti.o when using a cross-compiler
-# combined with --sysroot.
-XCFLAGS+=	-B${WORLDTMP}/usr/lib
-# Force using libc++ for external GCC.
-.if defined(X_COMPILER_TYPE) && \
-    ${X_COMPILER_TYPE} == gcc && ${X_COMPILER_VERSION} >= 40800
-XCXXFLAGS+=	-isystem ${WORLDTMP}/usr/include/c++/v1 -std=c++11 \
-		-nostdinc++
-.endif
 .elif ${WANT_COMPILER_TYPE} == clang || \
     (defined(X_COMPILER_TYPE) && ${X_COMPILER_TYPE} == clang)
 XCFLAGS+=	-target ${TARGET_TRIPLE}
Index: head/Makefile.libcompat
===================================================================
--- head/Makefile.libcompat
+++ head/Makefile.libcompat
@@ -100,22 +100,6 @@
 # Clang/GCC.
 LIBCOMPATCFLAGS+=	-B${LIBCOMPATTMP}/usr/lib${libcompat}
 
-.if ${WANT_COMPILER_TYPE} == gcc || \
-    (defined(X_COMPILER_TYPE) && ${X_COMPILER_TYPE} == gcc)
-# GCC requires -isystem when using a cross-compiler and --sysroot.  Note that
-# Makefile.inc1 only applies this with an external compiler but libcompat
-# always does since even in-tree GCC 4.2 needs this to override the built-in
-# sysroot path which --sysroot does not actually do for headers.
-LIBCOMPATCFLAGS+=	-isystem ${LIBCOMPATTMP}/usr/include
-# Force using libc++ for external GCC.
-.if defined(X_COMPILER_TYPE) && \
-    ${X_COMPILER_TYPE} == gcc && ${X_COMPILER_VERSION} >= 40800 && \
-    (${MK_CLANG_BOOTSTRAP} == "no" && ${MK_GCC_BOOTSTRAP} == "no")
-LIBCOMPATCXXFLAGS+=	-isystem ${LIBCOMPATTMP}/usr/include/c++/v1 -std=c++11 \
-			-nostdinc++
-.endif
-.endif
-
 # Yes, the flags are redundant.
 LIBCOMPATWMAKEENV+= \
 		INSTALL="sh ${.CURDIR}/tools/install.sh" \