Replace dot-dot relative pathing with SRCTOP-relative paths where possible

This reduces build output, need for recalculating paths, and makes it clearer
which paths are relative to what areas in the source tree. The change in
performance over a locally mounted UFS filesystem was negligible in my testing,
but this may more positively impact other filesystems like NFS.

LIBC_SRCTOP was left alone so Juniper (and other users) can continue to
manipulate lib/libc/Makefile (and other Makefile.inc's under lib/libc) as
include Makefiles with custom options.

Discussed with:	marcel, sjg
MFC after:	1 week
Reviewed by:	emaste
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D9207

lib/libc/Makefile

@@ -36,7 +36,7 @@ SHLIB_LDSCRIPT=libc_nossp.ldscript
 .endif
 SHLIB_LDSCRIPT_LINKS=libxnet.so
 WARNS?=	2
-CFLAGS+=-I${LIBC_SRCTOP}/include -I${LIBC_SRCTOP}/../../include
+CFLAGS+=-I${LIBC_SRCTOP}/include -I${SRCTOP}/include
 CFLAGS+=-I${LIBC_SRCTOP}/${LIBC_ARCH}
 .if ${MK_NLS} != "no"
 CFLAGS+=-DNLS

lib/libc/aarch64/string/Makefile.inc

@@ -4,7 +4,7 @@
 # https://git.linaro.org/toolchain/cortex-strings.git
 #
 
-.PATH: ${LIBC_SRCTOP}/../../contrib/cortex-strings/src/aarch64
+.PATH: ${SRCTOP}/contrib/cortex-strings/src/aarch64
 
 MDSRCS+=memchr.S \
 	memcmp.S \

lib/libc/arm/aeabi/Makefile.inc

@@ -21,7 +21,7 @@ SRCS+=	aeabi_vfp_double.S	\
 # libc. This causes issues when other parts of libc call these functions.
 # We work around this by including these functions in libc but mark them as
 # hidden so users of libc will not pick up these versions.
-.PATH: ${LIBC_SRCTOP}/../../contrib/compiler-rt/lib/builtins/arm
+.PATH: ${SRCTOP}/contrib/compiler-rt/lib/builtins/arm
 
 SRCS+=	aeabi_memcmp.S		\
 	aeabi_memcpy.S		\

lib/libc/capability/Makefile.inc

@@ -1,7 +1,7 @@
 # $FreeBSD$
 
 # capability sources
-.PATH: ${LIBC_SRCTOP}/../../sys/kern ${LIBC_SRCTOP}/capability
+.PATH: ${SRCTOP}/sys/kern ${LIBC_SRCTOP}/capability
 
 SRCS+=	subr_capability.c
 

lib/libc/gdtoa/Makefile.inc

@@ -10,11 +10,11 @@ GDTOASRCS+=dmisc.c dtoa.c gdtoa.c gethex.c gmisc.c \
 
 SYM_MAPS+=${LIBC_SRCTOP}/gdtoa/Symbol.map
 
-CFLAGS+=-I${LIBC_SRCTOP}/../../contrib/gdtoa
+CFLAGS+=-I${SRCTOP}/contrib/gdtoa
 
 .for src in ${GDTOASRCS}
 MISRCS+=gdtoa_${src}
 CLEANFILES+=gdtoa_${src}
-gdtoa_${src}: ${LIBC_SRCTOP}/../../contrib/gdtoa/${src} .NOMETA
+gdtoa_${src}: ${SRCTOP}/contrib/gdtoa/${src} .NOMETA
 	ln -sf ${.ALLSRC} ${.TARGET}
 .endfor

lib/libc/gen/Makefile.inc

@@ -152,11 +152,11 @@ SRCS+=	fts-compat.c \
 	unvis-compat.c
 .endif
 
-.PATH: ${LIBC_SRCTOP}/../../contrib/libc-pwcache
+.PATH: ${SRCTOP}/contrib/libc-pwcache
 SRCS+=	pwcache.c pwcache.h
 
-.PATH: ${LIBC_SRCTOP}/../../contrib/libc-vis
-CFLAGS+=	-I${LIBC_SRCTOP}/../../contrib/libc-vis
+.PATH: ${SRCTOP}/contrib/libc-vis
+CFLAGS+=	-I${SRCTOP}/contrib/libc-vis
 SRCS+=	unvis.c vis.c
 
 MISRCS+=modf.c

lib/libc/iconv/Makefile.inc

@@ -22,5 +22,5 @@ SRCS+=	iconv_compat.c
 SYM_MAPS+= ${LIBC_SRCTOP}/iconv/Symbol.map
 
 .if ${MK_ICONV} == yes
-.include "${LIBC_SRCTOP}/../libc_nonshared/Makefile.iconv"
+.include "${SRCTOP}/lib/libc_nonshared/Makefile.iconv"
 .endif

lib/libc/md/Makefile.inc

@@ -1,5 +1,5 @@
 # $FreeBSD$
 
-.PATH: ${LIBC_SRCTOP}/../libmd
+.PATH: ${SRCTOP}/lib/libmd
 
 SRCS+=	md5c.c

lib/libc/posix1e/Makefile.inc

@@ -5,7 +5,7 @@
 CFLAGS+=-D_ACL_PRIVATE
 
 # Copy kern/subr_acl_nfs4.c to the libc object directory.
-subr_acl_nfs4.c: ${LIBC_SRCTOP}/../../sys/kern/subr_acl_nfs4.c
+subr_acl_nfs4.c: ${SRCTOP}/sys/kern/subr_acl_nfs4.c
 	cat ${.ALLSRC} > ${.TARGET}
 
 SRCS+=	acl_branding.c			\

lib/libc/regex/grot/Makefile

@@ -5,7 +5,7 @@
 # Do not take -DPOSIX_MISTAKE out.  REGCFLAGS isn't important to you (it's
 # for my use in some special contexts).
 
-PATHS= ${.CURDIR:H} ${.CURDIR:H:H}/locale ${SRCTOP}/include
+PATHS= ${LIBC_SRCTOP}/regex ${LIBC_SRCTOP}/locale ${SRCTOP}/include
 .PATH: ${PATHS}
 
 CFLAGS+= -static -DPOSIX_MISTAKE -DREDEBUG $(REGCFLAGS)

lib/libc/resolv/Makefile.inc

@@ -9,4 +9,4 @@ SRCS+=	herror.c h_errno.c mtctxres.c res_comp.c res_data.c res_debug.c \
 
 SYM_MAPS+= ${LIBC_SRCTOP}/resolv/Symbol.map
 
-CFLAGS+=-I${LIBC_SRCTOP}/../libmd
+CFLAGS+=-I${SRCTOP}/lib/libmd

lib/libc/stdlib/jemalloc/Makefile.inc

@@ -9,18 +9,18 @@ JEMALLOCSRCS:= jemalloc.c arena.c atomic.c base.c bitmap.c chunk.c \
 
 SYM_MAPS+=${LIBC_SRCTOP}/stdlib/jemalloc/Symbol.map
 
-CFLAGS+=-I${LIBC_SRCTOP}/../../contrib/jemalloc/include
+CFLAGS+=-I${SRCTOP}/contrib/jemalloc/include
 
 .for src in ${JEMALLOCSRCS}
 MISRCS+=jemalloc_${src}
 CLEANFILES+=jemalloc_${src}
-jemalloc_${src}: ${LIBC_SRCTOP}/../../contrib/jemalloc/src/${src} .NOMETA
+jemalloc_${src}: ${SRCTOP}/contrib/jemalloc/src/${src} .NOMETA
 	ln -sf ${.ALLSRC} ${.TARGET}
 .endfor
 
 MAN+=jemalloc.3
 CLEANFILES+=jemalloc.3
-jemalloc.3: ${LIBC_SRCTOP}/../../contrib/jemalloc/doc/jemalloc.3 .NOMETA
+jemalloc.3: ${SRCTOP}/contrib/jemalloc/doc/jemalloc.3 .NOMETA
 	ln -sf ${.ALLSRC} ${.TARGET}
 
 MLINKS+= \

lib/libc/stdtime/Makefile.inc

@@ -1,14 +1,14 @@
 #	Makefile.inc,v 1.2 1994/09/13 21:26:01 wollman Exp
 # $FreeBSD$
 
-.PATH:	${LIBC_SRCTOP}/stdtime ${LIBC_SRCTOP}/../../contrib/tzcode/stdtime
+.PATH:	${LIBC_SRCTOP}/stdtime ${SRCTOP}/contrib/tzcode/stdtime
 
 SRCS+=	asctime.c difftime.c localtime.c strftime.c strptime.c timelocal.c \
 	time32.c
 
 SYM_MAPS+= ${LIBC_SRCTOP}/stdtime/Symbol.map
 
-CFLAGS+= -I${LIBC_SRCTOP}/../../contrib/tzcode/stdtime -I${LIBC_SRCTOP}/stdtime
+CFLAGS+= -I${SRCTOP}/contrib/tzcode/stdtime -I${LIBC_SRCTOP}/stdtime
 
 CFLAGS.localtime.c= -fwrapv
 

lib/libc/string/Makefile.inc

@@ -2,7 +2,7 @@
 # $FreeBSD$
 
 .PATH: ${LIBC_SRCTOP}/${LIBC_ARCH}/string ${LIBC_SRCTOP}/string
-.PATH: ${LIBC_SRCTOP}/../../sys/libkern
+.PATH: ${SRCTOP}/sys/libkern
 
 CFLAGS+= -I${LIBC_SRCTOP}/locale
 

lib/libc/sys/Makefile.inc

@@ -6,7 +6,7 @@
 
 # Include the generated makefile containing the *complete* list
 # of syscall names in MIASM.
-.include "${LIBC_SRCTOP}/../../sys/sys/syscall.mk"
+.include "${SRCTOP}/sys/sys/syscall.mk"
 
 # Include machine dependent definitions.
 #