Set up blank top_srcdir if building in source directory.

This means short, relative names are used for C source files when
compiling in the source directory.

* Makefile (CFLAGS): Exclude -iquote $(top_srcdir) arguments
if top_srcdir is blank. Remove slash after $(top_srcdir),
since the variable includes it now, if its value is not blank.
(SRCS, ABBREV, opt/%-win.o, lex.yy.c, y.tab.c, install): Remove slash
after $(top_srcdir).
(dbg/%.o, opt/%.o): Only include rules for depending
on $(top_srcdir)%.c prerequisite if top_srcdir is not blank.
In the blank case, the rules are redundant.

* configure: if configuring in the root of the source tree,
establish top_srcdir as blank, otherwise establish is as
an absolute path with a trailing slash.

3 files changed, 48 insertions, 19 deletions

diff --git a/ChangeLog b/ChangeLog
index 605b65c1..78d5637a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,25 @@
 2015-07-23  Kaz Kylheku  <kaz@kylheku.com>
 
+	Set up blank top_srcdir if building in source directory.
+
+	This means short, relative names are used for C source files when
+	compiling in the source directory.
+
+	* Makefile (CFLAGS): Exclude -iquote $(top_srcdir) arguments
+	if top_srcdir is blank. Remove slash after $(top_srcdir),
+	since the variable includes it now, if its value is not blank.
+	(SRCS, ABBREV, opt/%-win.o, lex.yy.c, y.tab.c, install): Remove slash
+	after $(top_srcdir).
+	(dbg/%.o, opt/%.o): Only include rules for depending
+	on $(top_srcdir)%.c prerequisite if top_srcdir is not blank.
+	In the blank case, the rules are redundant.
+
+	* configure: if configuring in the root of the source tree,
+	establish top_srcdir as blank, otherwise establish is as
+	an absolute path with a trailing slash.
+
+2015-07-23  Kaz Kylheku  <kaz@kylheku.com>
+
 	Split off test macros from ifa.tl into common file.
 
 	* Makefile (TESTS_OUT): Don't use find to hunt down tests;
diff --git a/Makefile b/Makefile
index ace97a2d..786c7ab0 100644
--- a/Makefile
+++ b/Makefile
@@ -26,10 +26,10 @@
 -include config/config.make
 
 VERBOSE :=
-CFLAGS := -iquote $(conf_dir) -iquote $(top_srcdir) \
+CFLAGS := -iquote $(conf_dir) $(if $(top_srcdir),-iquote $(top_srcdir)) \
           $(LANG_FLAGS) $(DIAG_FLAGS) \
           $(DBG_FLAGS) $(PLATFORM_FLAGS) $(EXTRA_FLAGS)
-CFLAGS += -iquote $(top_srcdir)/mpi
+CFLAGS += -iquote $(top_srcdir)mpi
 CFLAGS := $(filter-out $(REMOVE_FLAGS),$(CFLAGS))
 
 ifneq ($(subst g++,@,$(notdir $(CC))),$(notdir $(CC)))
@@ -54,10 +54,10 @@ OBJS-$(have_posix_sigs) += signal.o
 EXTRA_OBJS-$(add_win_res) += win/txr.res
 
 ifneq ($(have_git),)
-SRCS := $(addprefix $(top_srcdir)/,\
+SRCS := $(addprefix $(top_srcdir),\
                     $(filter-out lex.yy.c y.tab.c y.tab.h,\
                                  $(shell git --work-tree=$(top_srcdir) \
-                                             --git-dir=$(top_srcdir)/.git \
+                                             --git-dir=$(top_srcdir).git \
                                               ls-files "*.c" "*.h" "*.l" "*.y")))
 endif
 
@@ -84,7 +84,7 @@ V = $(if $(VERBOSE),,@)
 ABBREV = $(if $(VERBOSE),\
            @:,\
            @printf "%s %s -> %s\n" $(1) \
-	      "$(patsubst $(top_srcdir)/%,%,$(filter-out $(DEP_$@),$^))" $@)
+	      "$(patsubst $(top_srcdir)%,%,$(filter-out $(DEP_$@),$^))" $@)
 ABBREV3 = $(if $(VERBOSE),@:,@printf "%s %s -> %s\n" $(1) "$(3)" $(2))
 
 define DEPGEN
@@ -114,11 +114,13 @@ $(V)mkdir -p $(dir $@)
 $(V)windres -O coff -DTXR_VER=$(txr_ver) $< $@
 endef
 
-dbg/%.o: $(top_srcdir)/%.c
+ifneq ($(top_srcdir),)
+dbg/%.o: $(top_srcdir)%.c
 	$(call COMPILE_C_WITH_DEPS,)
 
-opt/%.o: $(top_srcdir)/%.c
+opt/%.o: $(top_srcdir)%.c
 	$(call COMPILE_C_WITH_DEPS,$(OPT_FLAGS))
+endif
 
 dbg/%.o: %.c
 	$(call COMPILE_C_WITH_DEPS,)
@@ -126,10 +128,10 @@ dbg/%.o: %.c
 opt/%.o: %.c
 	$(call COMPILE_C_WITH_DEPS,$(OPT_FLAGS))
 
-dbg/%-win.o: $(top_srcdir)/%.c
+dbg/%-win.o: $(top_srcdir)%.c
 	$(call COMPILE_C_WITH_DEPS,-DCONFIG_WIN_MAIN=1)
 
-opt/%-win.o: $(top_srcdir)/%.c
+opt/%-win.o: $(top_srcdir)%.c
 	$(call COMPILE_C_WITH_DEPS,-DCONFIG_WIN_MAIN=1 $(OPT_FLAGS))
 
 %.res: %.rc
@@ -182,7 +184,7 @@ $(call DEP,$(OBJS) $(EXTRA_OBJS-y),\
 
 $(call DEP,opt/lex.yy.o dbg/lex.yy.o,y.tab.h)
 
-lex.yy.c: $(top_srcdir)/parser.l
+lex.yy.c: $(top_srcdir)parser.l
 	$(call ABBREV,LEX)
 	$(V)rm -f $@
 	$(V)$(LEX) $(LEX_DBG_FLAGS) $<
@@ -195,7 +197,7 @@ y.tab.h: y.tab.c
 	  exit 1;                                                 \
 	fi
 
-y.tab.c: $(top_srcdir)/parser.y
+y.tab.c: $(top_srcdir)parser.y
 	$(call ABBREV,YACC)
 	$(V)rm -f y.tab.c
 	$(V)if $(YACC) -v -d $< ; then chmod a-w y.tab.c ; true ; else rm y.tab.c ; false ; fi
@@ -351,11 +353,11 @@ PREINSTALL := :
 install: $(PROG)
 	$(V)$(PREINSTALL)
 	$(call INSTALL,0755,txr$(EXE),$(DESTDIR)$(bindir))
-	$(call INSTALL,0444,$(top_srcdir)/LICENSE,$(DESTDIR)$(datadir))
-	$(call INSTALL,0444,$(top_srcdir)/METALICENSE,$(DESTDIR)$(datadir))
-	$(call INSTALL,0444,$(top_srcdir)/txr.1,$(DESTDIR)$(mandir)/man1)
+	$(call INSTALL,0444,$(top_srcdir)LICENSE,$(DESTDIR)$(datadir))
+	$(call INSTALL,0444,$(top_srcdir)METALICENSE,$(DESTDIR)$(datadir))
+	$(call INSTALL,0444,$(top_srcdir)txr.1,$(DESTDIR)$(mandir)/man1)
 	$(call INSTALL,0444,\
-	   $(addprefix $(top_srcdir)/share/txr/stdlib/,\
+	   $(addprefix $(top_srcdir)share/txr/stdlib/,\
 	                  *.txr *.tl),\
 	   $(DESTDIR)$(datadir)/stdlib)
 
diff --git a/configure b/configure
index 6fc5e065..11f30da4 100755
--- a/configure
+++ b/configure
@@ -535,11 +535,18 @@ done
 source_dir="$(dirname $0)"
 
 #
-# Compute an absolute path to the source directory.
+# If building in a separate directory, establish top_srcdir as
+# an absolute path to the source directory, with a trailing slash.
+# Otherwise top_srcdir is blank.
 #
-top_srcdir="$(cd "$source_dir" ; pwd -P)"
 
-printf "Checking source directory %s ..." "$top_srcdir"
+if [ "$source_dir" = "." ] ; then
+  top_srcdir=""
+else
+  top_srcdir="$(cd "$source_dir" ; pwd -P)"/
+fi
+
+printf "Checking source directory \"%s\" ..." "$top_srcdir"
 
 case "$top_srcdir" in
 " "* | *" "* | *" " )
@@ -715,7 +722,7 @@ conftest_syms()
 # But this is pointless if we have no git repo.
 # "have_git" means we have a repo, and git.
 #
-if [ -d $top_srcdir/.git ] ; then 
+if [ -d $top_srcdir.git ] ; then 
   printf "Checking whether we have git ... "
 
   if git --version > /dev/null 2> /dev/null ; then