diff --git a/lib/atf/libatf-c/Makefile b/lib/atf/libatf-c/Makefile
--- a/lib/atf/libatf-c/Makefile
+++ b/lib/atf/libatf-c/Makefile
@@ -28,22 +28,6 @@
 .include <src.opts.mk>
 .include <bsd.init.mk>
 
-# Store the toolchain executable in ATF_BUILD_{CC,CPP,CXX} to ensure other
-# values -- like -target, -B ..., etc -- don't get leaked into the tests.
-#
-# Be sure to omit ${CCACHE_BIN} (if specified) from the variable as it gets
-# automatically appended to the variables in bsd.compiler.mk when
-# ${MK_CCACHE_BUILD} != no.
-ATF_BUILD_CC:=		${CC:N${CCACHE_BIN}:[1]}
-ATF_BUILD_CPP:=		${CPP:N${CCACHE_BIN}:[1]}
-ATF_BUILD_CXX:=		${CXX:N${CCACHE_BIN}:[1]}
-
-# Only capture defines, includes, linker flags, optimization levels, warnings
-# and preprocessor flags when building ATF_BUILD_{C,CPP,CXX}FLAGS.
-ATF_BUILD_CFLAGS:=	${CFLAGS:M-[DILOWf]*}
-ATF_BUILD_CPPFLAGS:=	${CPPFLAGS:M-[DILOWf]*}
-ATF_BUILD_CXXFLAGS:=	${CXXFLAGS:M-[DILOWf]*}
-
 PACKAGE=	tests
 LIB=		atf-c
 PRIVATELIB=	true
@@ -54,12 +38,6 @@
 .PATH:		${ATF}/atf-c
 .PATH:		${ATF}/atf-c/detail
 
-CFLAGS+=	-DATF_BUILD_CC='"${ATF_BUILD_CC}"'
-CFLAGS+=	-DATF_BUILD_CFLAGS='"${ATF_BUILD_CFLAGS}"'
-CFLAGS+=	-DATF_BUILD_CPP='"${ATF_BUILD_CPP}"'
-CFLAGS+=	-DATF_BUILD_CPPFLAGS='"${ATF_BUILD_CPPFLAGS}"'
-CFLAGS+=	-DATF_BUILD_CXX='"${ATF_BUILD_CXX}"'
-CFLAGS+=	-DATF_BUILD_CXXFLAGS='"${ATF_BUILD_CXXFLAGS}"'
 CFLAGS+=	-I${ATF}
 CFLAGS+=	-I${.CURDIR}
 CFLAGS+=	-I.
@@ -160,5 +138,6 @@
 HAS_TESTS=
 SUBDIR.${MK_TESTS}+= tests
 
+.include "Makefile.inc"
 .include "../common.mk"
 .include <bsd.lib.mk>
diff --git a/lib/atf/libatf-c/Makefile.inc b/lib/atf/libatf-c/Makefile.inc
--- a/lib/atf/libatf-c/Makefile.inc
+++ b/lib/atf/libatf-c/Makefile.inc
@@ -1,3 +1,10 @@
 # $FreeBSD$
 
 .include "../Makefile.inc"
+
+CFLAGS+=	-DATF_BUILD_CC='"cc"'
+CFLAGS+=	-DATF_BUILD_CFLAGS='"-Wall"'
+CFLAGS+=	-DATF_BUILD_CPP='"cpp"'
+CFLAGS+=	-DATF_BUILD_CPPFLAGS='""'
+CFLAGS+=	-DATF_BUILD_CXX='"c++"'
+CFLAGS+=	-DATF_BUILD_CXXFLAGS='"-Wall"'
diff --git a/lib/atf/libatf-c/tests/Makefile b/lib/atf/libatf-c/tests/Makefile
--- a/lib/atf/libatf-c/tests/Makefile
+++ b/lib/atf/libatf-c/tests/Makefile
@@ -35,4 +35,5 @@
 TEST_METADATA.${_T}+=	required_programs="cc"
 .endfor
 
+.include "Makefile.inc"
 .include <bsd.test.mk>