Allow to easily build all optional modules

This patch adds a CONFIG_EVERYTHING flag to the Makefile
that sets all CONFIG_* flags to "yes" if they were "no".

This provides a comfortable way to ensure maximum code exposure
to tools like coverity[0] or clang's scan-build.

[0] https://scan.coverity.com/projects/1020

Corresponding to flashrom svn r1869.

Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/Makefile b/Makefile
index 8cb39ed..a36628c 100644
--- a/Makefile
+++ b/Makefile
@@ -467,6 +467,13 @@
 # Disable wiki printing by default. It is only useful if you have wiki access.
 CONFIG_PRINT_WIKI ?= no
 
+# Enable all features if CONFIG_EVERYTHING=yes is given
+ifeq ($(CONFIG_EVERYTHING), yes)
+$(foreach var, $(filter CONFIG_%, $(.VARIABLES)),\
+	$(if $(filter no, $($(var))),\
+		$(eval $(var)=yes)))
+endif
+
 # Bitbanging SPI infrastructure, default off unless needed.
 ifeq ($(CONFIG_RAYER_SPI), yes)
 override CONFIG_BITBANG_SPI = yes