Merge pull request #169 from eli-schwartz/command-v

build: fix building manpages on systems where asciidoc is already installed

Author: tummychow

Documentation/Makefile

@@ -1,7 +1,7 @@
 build-manpage: git-absorb.1
 
 git-absorb.1: git-absorb.adoc
-	$(if $(shell which a2x),,$(error "No a2x in PATH; install asciidoc."))
+	$(if $(shell command -v a2x),,$(error "No a2x in PATH; install asciidoc."))
 	$(info Building manpage. This may take a few moments...)
 	a2x -L -d manpage -f manpage git-absorb.adoc --attribute man-version=${GA_VERSION}