config: make -Werror optional and off by default

Allow end users to build the code even if, for example, warnings are
added with new compilers versions.

-Werror is still enforced for automated builds.

Change-Id: I567009d55cf5b941c452bd41d09f75d03b037209
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>

CONFIG

@@ -34,6 +34,9 @@
 # Build with debug logging. Turn off for performance testing and normal usage
 CONFIG_DEBUG?=n
 
+# Treat warnings as errors (fail the build on any warning).
+CONFIG_WERROR?=n
+
 # Build with code coverage instrumentation.
 CONFIG_COVERAGE?=n
 

mk/spdk.common.mk

@@ -43,7 +43,11 @@ endif
 
 OS := $(shell uname)
 
-COMMON_CFLAGS = -g $(C_OPT) -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wmissing-declarations -Wstrict-prototypes -Werror -fno-strict-aliasing -march=native -m64 -I$(SPDK_ROOT_DIR)/include
+COMMON_CFLAGS = -g $(C_OPT) -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wmissing-declarations -Wstrict-prototypes -fno-strict-aliasing -march=native -m64 -I$(SPDK_ROOT_DIR)/include
+
+ifeq ($(CONFIG_WERROR), y)
+COMMON_CFLAGS += -Werror
+endif
 
 COMMON_CFLAGS += -Wformat -Wformat-security -Wformat-nonliteral
 

scripts/autotest_common.sh

@@ -1,7 +1,7 @@
 set -xe
 ulimit -c unlimited
 
-MAKECONFIG='CONFIG_DEBUG=y'
+MAKECONFIG='CONFIG_DEBUG=y CONFIG_WERROR=y'
 
 case `uname` in
 	FreeBSD)

unittest.sh

@@ -2,7 +2,7 @@
 
 set -xe
 
-make -C test/lib/nvme/unit
+make -C test/lib/nvme/unit CONFIG_WERROR=y
 
 test/lib/nvme/unit/nvme_c/nvme_ut
 test/lib/nvme/unit/nvme_ctrlr_c/nvme_ctrlr_ut
@@ -10,6 +10,6 @@ test/lib/nvme/unit/nvme_ctrlr_cmd_c/nvme_ctrlr_cmd_ut
 test/lib/nvme/unit/nvme_ns_cmd_c/nvme_ns_cmd_ut
 test/lib/nvme/unit/nvme_qpair_c/nvme_qpair_ut
 
-make -C test/lib/ioat/unit
+make -C test/lib/ioat/unit CONFIG_WERROR=y
 
 test/lib/ioat/unit/ioat_ut