diff --git a/Makefile b/Makefile
index aba8019..0f166a7 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 PACKAGE = 'build_zsh'
-VERSION = '0.3.1'
+VERSION = '0.4.0'
 
 PREFIX := /usr/local
 BINDIR := $(PREFIX)/bin
@@ -285,7 +285,7 @@ $(PACKAGE)-$(VERSION).tar.bz2: distdir
 		$(PACKAGE)-$(VERSION)/Makefile
 
 help:
-	@echo ' :: build_zsh-0.3.1'
+	@echo ' :: build_zsh-0.4.0'
 	@echo ''
 	@echo 'Generic targets:'
 	@echo '    - help           Prints this help message.'
diff --git a/build.zsh.in b/build.zsh.in
index 124419f..64e4d81 100644
--- a/build.zsh.in
+++ b/build.zsh.in
@@ -204,7 +204,12 @@ done
 
 function main {
 	typeset -a prefixes directories
-	typeset -A ldflags cflags sources type depends install auto filename nodist
+
+	# FIXME: We may want those to be defined somewhere else.
+	typeset -A ldflags cflags crflags
+
+	typeset -A sources type depends install auto filename nodist
+
 	typeset -A chmod
 	typeset -a tests
 
diff --git a/build/crystal.zsh b/build/crystal.zsh
index 62c45c0..966ce40 100644
--- a/build/crystal.zsh
+++ b/build/crystal.zsh
@@ -2,7 +2,7 @@
 function crystal.build {
 	write "${target}: ${src[@]} ${depends[$target]} $(dirdep $target)"
 	write "\t@echo '${fg_bold[magenta]}  CR >    ${fg_bold[white]}$target${reset_color}'"
-	write "\t${Q}crystal ${src[@]} -o '${target}'"
+	write "\t${Q}crystal build ${crflags[$target]:---release} \$(CRFLAGS) ${src[@]} -o '${target}'"
 
 	write "\n"
 }