ktap: add configs for elfutils and ffi

libelf (elfutils) is required for resolving symbols in DSO and for sdt (taken
from ktap docs). The earlier v0.4 recipe built ktap against libelf if it was
found, thus enable it per default.

FFI needs to be enabled for both userspace and kernel module. Currently, it is
only supported for x86_64 (enforced when building ktap-module).

Signed-off-by: Anders Darander <anders@chargestorm.se>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

meta-oe/recipes-kernel/ktap/ktap-module_0.4.bb

@@ -6,8 +6,11 @@ DESCRIPTION = "KTAP is a scripting dynamic tracing tool for Linux"
 
 inherit module
 
+# Available package configs: ffi (only supported on x86_64)
+PACKAGECONFIG ?= ""
+
 # Only build the module
-MAKE_TARGETS = "mod"
+MAKE_TARGETS = "${@base_contains('PACKAGECONFIG', 'ffi', 'FFI=1', '', d)} mod"
 
 # Kernel module packages MUST begin with 'kernel-module-', otherwise
 # multilib image generation can fail.

meta-oe/recipes-kernel/ktap/ktap.inc

@@ -9,3 +9,5 @@ SRC_URI = "git://github.com/ktap/ktap.git"
 
 S = "${WORKDIR}/git"
 
+# Package config is abused as a general compile time configuration tool.
+PACKAGECONFIG[ffi] = ""

meta-oe/recipes-kernel/ktap/ktap_0.4.bb

@@ -5,8 +5,17 @@ require ktap.inc
 SUMMARY = "KTAP is a scripting dynamic tracing tool for Linux"
 DEPENDS = "ktap-module"
 
+#Available package configs:
+# libelf - needed to resolve symbols in DSO and for sdt
+# ffi    - only supports x86_64 for now!. Needs to be enabled for ktap-module too.
+PACKAGECONFIG ?= "libelf"
+
+PACKAGECONFIG[libelf] = ",,elfutils"
+
 # Only build the userspace app
-EXTRA_OEMAKE = "ktap"
+EXTRA_OEMAKE = "${@base_contains('PACKAGECONFIG', 'libelf', '', 'NO_LIBELF=1', d)} \
+             ${@base_contains('PACKAGECONFIG', 'ffi', 'FFI=1', '', d)} \
+             ktap"
 
 do_install() {
     install -d ${D}${bindir}