build: add option to disable building examples

If examples are not needed using that option can reduce build time and
output logs so it is easier to spot most important issues/warnings.

Signed-off-by: Jacek Kalwas <jacek.kalwas@intel.com>
Change-Id: Id279cba96ddf25d50a8748555d511d21f243bd7e
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/1047
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

CONFIG

@@ -73,6 +73,9 @@ CONFIG_TSAN=n
 # Build tests
 CONFIG_TESTS=y
 
+# Build examples
+CONFIG_EXAMPLES=y
+
 # Directory that contains the desired SPDK environment library.
 # By default, this is implemented using DPDK.
 CONFIG_ENV=

Makefile

@@ -39,7 +39,8 @@ include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 DIRS-y += lib
 DIRS-y += module
 DIRS-$(CONFIG_SHARED) += shared_lib
-DIRS-y += examples app include
+DIRS-y += app include
+DIRS-$(CONFIG_EXAMPLES) += examples
 DIRS-$(CONFIG_TESTS) += test
 DIRS-$(CONFIG_IPSEC_MB) += ipsecbuild
 DIRS-$(CONFIG_ISAL) += isalbuild

configure

@@ -33,6 +33,7 @@ function usage()
 	echo " --enable-pgo-capture      Enable generation of profile guided optimization data"
 	echo " --enable-pgo-use          Use previously captured profile guided optimization data"
 	echo " --disable-tests           Disable building of tests"
+	echo " --disable-examples        Disable building of examples"
 	echo ""
 	echo "Specifying Dependencies:"
 	echo "--with-DEPENDENCY[=path]   Use the given dependency. Optionally, provide the"
@@ -240,6 +241,12 @@ for i in "$@"; do
 		--disable-tests)
 			CONFIG[TESTS]=n
 			;;
+		--enable-examples)
+			CONFIG[EXAMPLES]=y
+			;;
+		--disable-examples)
+			CONFIG[EXAMPLES]=n
+			;;
 		--enable-werror)
 			CONFIG[WERROR]=y
 			;;