crash-cross-canadian: fix build, including on clang based SDKs

The cross-canadian variant did not build. Several issues:

1. DEPENDS used :append on top of crash.inc's target DEPENDS. cross-canadian
   does not remap DEPENDS to nativesdk, so the target zlib/readline/ncurses/
   gmp/mpfr stayed in the dependency set and staged a real target usr/lib into
   the recipe sysroot, clashing with the nativesdk toolchain (clang-glue
   provides usr/lib as a symlink) during do_prepare_recipe_sysroot. Override
   DEPENDS with the nativesdk set instead (matching gdb-cross-canadian) and add
   the -native build tools the build needs.

2. do_compile hardcoded ${HOST_PREFIX}gcc, which does not exist on clang based
   SDKs (TOOLCHAIN = "clang"), giving "C compiler cannot create executables".
   Use the toolchain-aware ${CC}/${CXX} like the other variants.

3. crash's gdb merge re-enters the top-level crash Makefile from gdb's link
   rule ("make -C ../.. ... library") without passing the compiler, so crash's
   own objects fell back to the Makefile default $(CROSS_COMPILE)gcc and failed
   to find a compiler on clang SDKs. Forward CC/CXX through that recursion in
   the bundled gdb-16.2.patch; this is harmless where ${cross}-gcc exists.

Verified by building crash, crash-native, crash-cross and
crash-cross-canadian-x86-64 for a clang based SDK (qemux86-64).

Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-oe/recipes-kernel/crash/crash-cross-canadian_9.0.2.bb

@@ -6,18 +6,25 @@ BPN = "crash"
 
 require crash.inc
 
-DEPENDS:append = " \
+# cross-canadian.bbclass does not remap DEPENDS to their nativesdk variants, so
+# override (rather than append to) the target DEPENDS pulled in from crash.inc.
+# Leaving the target zlib/readline/ncurses/gmp/mpfr in place would stage a real
+# target usr/lib into the recipe sysroot and clash with the nativesdk toolchain
+# (e.g. clang-glue, which provides usr/lib as a symlink) during
+# do_prepare_recipe_sysroot.
+DEPENDS = " \
     nativesdk-ncurses \
     nativesdk-expat \
     nativesdk-gettext \
     nativesdk-gmp \
     nativesdk-mpfr \
-    nativesdk-readline \
     nativesdk-zlib \
     virtual/nativesdk-cross-cc \
     virtual/nativesdk-cross-binutils \
-    virtual/nativesdk-compilerlibs \
     virtual/nativesdk-libc \
+    coreutils-native \
+    bison-native \
+    flex-native \
 "
 
 RDEPENDS:${PN} = "nativesdk-liblzma"
@@ -43,9 +50,11 @@ EXTRA_OEMAKE:class-cross-canadian = ' \
                     ac_cv_header_sys_procfs_h=yes" \
 '
 
-# Force the SDK cross-compiler during the command execution phase
+# Build with the SDK cross-compiler. Use the toolchain-aware ${CC}/${CXX}
+# rather than a hardcoded ${HOST_PREFIX}gcc so this also works for clang based
+# SDKs (TOOLCHAIN = "clang"), which provide no ...-gcc.
 do_compile() {
-    oe_runmake ${EXTRA_OEMAKE} CC="${HOST_PREFIX}gcc ${HOST_CC_ARCH}" CXX="${HOST_PREFIX}g++ ${HOST_CC_ARCH}" RECIPE_SYSROOT=${RECIPE_SYSROOT}
+    oe_runmake ${EXTRA_OEMAKE} CC="${CC}" CXX="${CXX}" RECIPE_SYSROOT=${RECIPE_SYSROOT}
 }
 
 # To ship crash into your sdk, you should create/update a packagegroup-cross-canadian.bbappend and

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

@@ -99,6 +99,13 @@ do_compile:prepend() {
     sed -i -e 's/#define TARGET_CFLAGS_MIPS_ON_X86_64.*/#define TARGET_CFLAGS_MIPS_ON_X86_64\t\"TARGET_CFLAGS=-D_FILE_OFFSET_BITS=64\"/g' ${S}/configure.c
     sed -i 's/>/>/g' ${S}/Makefile
 
+    # The crash gdb merge step re-enters the top-level crash Makefile from gdb's
+    # link rule ("make -C ../.. ... library") without passing the compiler, so
+    # crash's own objects fall back to the Makefile default $(CROSS_COMPILE)gcc.
+    # That only happens to work when a ${cross}-gcc exists; on clang toolchains
+    # (and any gcc-less SDK) it fails. Forward CC/CXX through that recursion.
+    sed -i 's|GDB_FLAGS=-DGDB_16_2 library|GDB_FLAGS=-DGDB_16_2 CC="$(CC)" CXX="$(CXX)" library|' ${S}/gdb-16.2.patch
+
     # 5. Return to the active workspace build root to merge downstream additions
     cd ${B}
     bbnote "Applying the native upstream crash integration patch onto the GDB source tree..."