Rename VERSION to VERSION.stamp

-I$(top_srcdir) is not usable on macOS due to a conflicting C++ header
 `version`.

Makefile.am

@@ -9,7 +9,7 @@ include $(top_srcdir)/aminclude_static.am
 ACLOCAL_AMFLAGS = -I m4
 SUBDIRS = scripts src man conf
 EXTRA_DIST = autogen.sh ocb-license.html README.md COPYING.iOS
-BUILT_SOURCES = VERSION
+BUILT_SOURCES = VERSION.stamp
 AM_DISTCHECK_CONFIGURE_FLAGS += --enable-compile-warnings=distcheck --enable-examples --enable-syslog
 
 # AX_CODE_COVERAGE configuration
@@ -31,22 +31,22 @@ OCLINT_OPTIONS = -enable-global-analysis -max-priority-2=1000 -max-priority-3=10
 	-rc SHORT_VARIABLE_NAME=1 \
 	-rc MINIMUM_CASES_IN_SWITCH=2
 
-.PHONY:	VERSION
+.PHONY:	VERSION.stamp
 
-VERSION:
+VERSION.stamp:
 	@echo @PACKAGE_STRING@ > VERSION.dist
 	@set -e; if git describe --dirty --always > VERSION.git 2>&1 && \
 		[ -z `git rev-parse --show-prefix` ]; then \
-		if ! diff -q VERSION.git VERSION > /dev/null 2>&1; then \
-			mv -f VERSION.git VERSION; \
+		if ! diff -q VERSION.git VERSION.stamp > /dev/null 2>&1; then \
+			mv -f VERSION.git VERSION.stamp; \
 		fi; \
-	elif ! diff -q VERSION.dist VERSION > /dev/null 2>&1; then \
-		mv -f VERSION.dist VERSION; \
+	elif ! diff -q VERSION.dist VERSION.stamp > /dev/null 2>&1; then \
+		mv -f VERSION.dist VERSION.stamp; \
 	fi
 	@rm -f VERSION.dist VERSION.git
 
 clean-local:
-	@rm -rf VERSION cov-int mosh-coverity.txz compile_commands.json
+	@rm -rf VERSION.stamp cov-int mosh-coverity.txz compile_commands.json
 
 # Linters and static checkers, for development only.  Not included in
 # build dependencies, and outside of Automake processing.