Minor build system improvements - force default shell.

[pub/USBasp.git] / LUFA / Build / lufa.doxygen.in

diff --git a/LUFA/Build/lufa.doxygen.in b/LUFA/Build/lufa.doxygen.in
index 2d8c28d..baca62f 100644 (file)
--- a/LUFA/Build/lufa.doxygen.in
+++ b/LUFA/Build/lufa.doxygen.in
@@ -45,9 +45,11 @@ LUFA_BUILD_PROVIDED_MACROS +=
 #
 # -----------------------------------------------------------------------------
 
-ERROR_IF_UNSET   = $(if $(filter undefined, $(origin $(strip $(1)))), $(error Makefile $(strip $(1)) value not set))
-ERROR_IF_EMPTY   = $(if $(strip $($(strip $(1)))), , $(error Makefile $(strip $(1)) option cannot be blank))
-ERROR_IF_NONBOOL = $(if $(filter Y N, $($(strip $(1)))), , $(error Makefile $(strip $(1)) option must be Y or N))
+SHELL = /bin/sh
+
+ERROR_IF_UNSET   ?= $(if $(filter undefined, $(origin $(strip $(1)))), $(error Makefile $(strip $(1)) value not set))
+ERROR_IF_EMPTY   ?= $(if $(strip $($(strip $(1)))), , $(error Makefile $(strip $(1)) option cannot be blank))
+ERROR_IF_NONBOOL ?= $(if $(filter Y N, $($(strip $(1)))), , $(error Makefile $(strip $(1)) option must be Y or N))
 
 # Default values of optionally user-supplied variables
 DOXYGEN_CONF            ?= Doxygen.conf