tclibc-newlib: Adds a new TCLIBC variant to build with newlib as C library

This patch adds the posibility to build using TCLIBC=newlib.

It allows users to build baremetal applications with the use of a
C library.

Newlib is a lightweight C library meant to be used on embedded systems,
it is meant to be easily portable for new platforms and to provide
basic functionality on them, by design, it provides stubs for some of
these core functions declared as weak, so they can be built correctly
and then linked against some other library which provides specifics
about the platform being used if need be, libgloss takes care of these
in some cases, but it can also be extended, this patch also allows the
user to easily add other libraries to it by adding them to
NEWLIB_EXTENDED for this specific reason.

(From OE-Core rev: 9f0570351a7b0877aa50efff5fe9a9ef368cb38f)

Signed-off-by: Alejandro Enedino Hernandez Samaniego <alejandr@xilinx.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/cross-canadian.bbclass

@@ -30,7 +30,7 @@ python () {
     if d.getVar("MODIFYTOS") != "1":
         return
 
-    if d.getVar("TCLIBC") == "baremetal":
+    if d.getVar("TCLIBC") in [ 'baremetal', 'newlib' ]:
         return
 
     tos = d.getVar("TARGET_OS")

meta/conf/distro/include/tclibc-newlib.inc

@@ -0,0 +1,44 @@
+#
+# Newlib configuration
+#
+
+LIBCEXTENSION = "-newlib"
+LIBCOVERRIDE = ":libc-newlib"
+
+PREFERRED_PROVIDER_virtual/libc ?= "newlib"
+PREFERRED_PROVIDER_virtual/libiconv ?= "newlib"
+PREFERRED_PROVIDER_virtual/libintl ?= "newlib"
+PREFERRED_PROVIDER_virtual/nativesdk-libintl ?= "nativesdk-glibc"
+PREFERRED_PROVIDER_virtual/nativesdk-libiconv ?= "nativesdk-glibc"
+
+DISTRO_FEATURES_BACKFILL_CONSIDERED += "ldconfig"
+
+#USE_NLS ?= "no"
+
+IMAGE_LINGUAS = ""
+
+LIBC_DEPENDENCIES = "\
+    newlib-dbg \
+    newlib-dev \
+    libgloss \
+    libgloss-dev \
+    libgloss-dbg \
+    libgcc-dev \
+    libgcc-dbg \
+    "
+
+# compilerlibs defaults to gcc-runtime, but we get runtime from libgloss
+# we set ASSUME_PROVIDED because we cant set PREFERRED_PROVIDER
+# for compilerlibs since its overridden by tcmode-default
+ASSUME_PROVIDED += "virtual/${TARGET_PREFIX}compilerlibs virtual/crypt"
+
+# Its useful to be able to extend newlib, but we dont provide a native variant of libgloss
+NEWLIB_EXTENDED ?=  "libgloss libgcc"
+BASE_DEFAULT_DEPS_append_class-target = " ${NEWLIB_EXTENDED}"
+
+TARGET_OS = "elf"
+TARGET_OS_arm = "eabi"
+
+TOOLCHAIN_HOST_TASK ?= "packagegroup-cross-canadian-${MACHINE}"
+TOOLCHAIN_TARGET_TASK ?= "${LIBC_DEPENDENCIES}"
+TOOLCHAIN_NEED_CONFIGSITE_CACHE_remove = "zlib ncurses"

meta/recipes-core/newlib/newlib_3.0.0.bb

@@ -14,3 +14,6 @@ do_install_append() {
 	# Remove original directory
 	rmdir ${D}${prefix}/${TARGET_SYS}
 }
+
+# No rpm package is actually created but -dev depends on it, avoid dnf error
+RDEPENDS_${PN}-dev_libc-newlib = ""

meta/recipes-devtools/gcc/libgcc-common.inc

@@ -47,8 +47,13 @@ do_install () {
 do_install_append_libc-baremetal () {
 	rmdir ${D}${base_libdir}
 }
+do_install_append_libc-newlib () {
+	rmdir ${D}${base_libdir}
+}
 
+# No rpm package is actually created but -dev depends on it, avoid dnf error
 RDEPENDS_${PN}-dev_libc-baremetal = ""
+RDEPENDS_${PN}-dev_libc-newlib = ""
 
 BBCLASSEXTEND = "nativesdk"