Handle missing git in build env.

Makefile.in

@@ -49,10 +49,12 @@ CFG_RUSTCLIB :=$(call CFG_LIB_NAME,rustc)
 # version-string calculation
 CFG_GIT_DIR := $(CFG_SRC_DIR).git
 CFG_VERSION := prerelease
+ifneq ($(wildcard $(CFG_GIT)),)
 ifneq ($(wildcard $(CFG_GIT_DIR)),)
     CFG_VERSION += $(shell git --git-dir=$(CFG_GIT_DIR) log -1 \
                      --pretty=format:'(%h %ci)')
 endif
+endif
 
 ifdef CFG_DISABLE_VALGRIND
   $(info cfg: disabling valgrind (CFG_DISABLE_VALGRIND))

configure

@@ -193,11 +193,11 @@ putvar CFG_CPUTYPE
 putvar CFG_CONFIGURE_ARGS
 
 step_msg "looking for build programs"
-probe_need CFG_GIT          git
 probe_need CFG_PERL         perl
 probe_need CFG_PYTHON       python
 probe_need CFG_CURL         curl
 
+probe CFG_GIT          git
 probe CFG_CLANG            clang++
 probe CFG_GCC              gcc
 probe CFG_LLVM_CONFIG      llvm-config

mk/docs.mk

@@ -3,8 +3,9 @@
 ######################################################################
 
 doc/version.texi: $(MKFILES) rust.texi
-	(cd $(S) && git log -1 \
-      --pretty=format:'@macro gitversion%n%h %ci%n@end macro%n') >$@
+	echo "@macro gitversion" >$@
+	echo $(CFG_VERSION) >>$@
+	echo "@end macro" >>$@
 
 doc/%.pdf: %.texi doc/version.texi
 	texi2pdf --batch -I doc -o $@ --clean $<