lib: add a version string

Signed-off-by: Zygo Blaxell <bees@furryterror.org>

include/crucible/version.h

@@ -0,0 +1,8 @@
+#ifndef CRUCIBLE_VERSION_H
+#define CRUCIBLE_VERSION_H
+
+namespace crucible {
+	extern const char *VERSION;
+}
+
+#endif CRUCIBLE_VERSION_H

lib/.gitignore

@@ -0,0 +1 @@
+.version.*

lib/Makefile

@@ -13,6 +13,7 @@ OBJS = \
 	string.o \
 	time.o \
 	uuid.o \
+	.version.o \
 
 include ../makeflags
 
@@ -21,6 +22,10 @@ depends.mk: *.c *.cc
 	for x in *.cc; do $(CXX) $(CXXFLAGS) -M "$$x"; done >> depends.mk.new
 	mv -fv depends.mk.new depends.mk
 
+.version.cc: Makefile ../makeflags *.c *.cc ../include/crucible/*.h
+	echo "namespace crucible { const char *VERSION = \"$(shell git describe --always --dirty || echo UNKNOWN)\"; }" > .version.new.cc
+	mv -f .version.new.cc .version.cc
+
 -include depends.mk
 
 %.o: %.c