[yocto] Libtoo sysrootl issue when testing machine specific sysroot

[Xu, Dongxiao]

Hi Richard,

When testing the machine specific sysroot patchset for atom-pc and emenlow machines, it exposed a libtool issue that, after the built of "Machine A", and then try to build "Machine B" of the same architecture, those "-L" paths generated by libtool still points to the "Machine A" sysroot, which is definitely not correct and may have issues.

One example is like the following, after built of emenlow, and then try to build atom-pc, the sysroot is points to atom-pc paths, however some "-L" paths point to emenlow directories.

/distro/dongxiao/build-core2/tmp/sysroots/x86_64-linux/usr/bin/core2-poky-linux/i586-poky-linux-gcc -m32 -march=core2 -msse3 -mtune=generic -mfpmath=sse --sysroot=/distro/dongxiao/build-core2/tmp/sysroots/atom-pc -DHAVE_DIX_CONFIG_H -Wall -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Wnested-externs -fno-strict-aliasing -Wbad-function-cast -Wformat=2 -Wold-style-definition -Wdeclaration-after-statement -D_BSD_SOURCE -DHAS_FCHOWN -DHAS_STICKY_DIR_BIT -I/distro/dongxiao/build-core2/tmp/sysroots/atom-pc/usr/include/pixman-1 -I/distro/dongxiao/build-core2/tmp/sysroots/atom-pc/usr/include/freetype2 -I../../include -I../../include -I../../Xext -I../../composite -I../../damageext -I../../xfixes -I../../Xi -I../../mi -I../../miext/shadow -I../../miext/damage -I../../render -I../../randr -I../../fb -fvisibility=hidden -DHAVE_XORG_CONFIG_H -fvisibility=hidden -DXF86PM -fexpensive-optimizations -fomit-frame-pointer -frename-registers -O2 -ggdb -feliminate-unused-debug-types -Wl,-O1 -Wl,--as-needed -o .libs/Xorg xorg.o -Wl,--export-dynamic  ../../dix/.libs/libmain.a ./.libs/libxorg.a -L/distro/dongxiao/build-core2/tmp/sysroots/emenlow/usr/lib /distro/dongxiao/build-core2/tmp/sysroots/atom-pc/usr/lib/libudev.so /distro/dongxiao/build-core2/tmp/sysroots/atom-pc/usr/lib/libgcrypt.so /distro/dongxiao/build-core2/tmp/sysroots/emenlow/usr/lib/libgpg-error.so -ldl /distro/dongxiao/build-core2/tmp/sysroots/atom-pc/usr/lib/libpciaccess.so -lpthread /distro/dongxiao/build-core2/tmp/sysroots/atom-pc/usr/lib/libpixman-1.so /distro/dongxiao/build-core2/tmp/sysroots/atom-pc/usr/lib/libXfont.so /distro/dongxiao/build-core2/tmp/sysroots/emenlow/usr/lib/libfreetype.so /distro/dongxiao/build-core2/tmp/sysroots/emenlow/usr/lib/libfontenc.so /distro/dongxiao/build-core2/tmp/sysroots/emenlow/usr/lib/libz.so /distro/dongxiao/build-core2/tmp/sysroots/atom-pc/usr/lib/libXau.so /distro/dongxiao/build-core2/tmp/sysroots/atom-pc/usr/lib/libXdmcp.so -lm


This problem happens when building atom-pc and emenlow since some libraries they are using are not the same.

This issue should also exist for qemuppc and mpc8315e-rdb build but it isn't exposed during my pervious testings, maybe because these files between the two machines are the same. 

We saw we have plan to add libtool sysroot support and remove its workaround, http://bugzilla.pokylinux.org/show_bug.cgi?id=353, I think this should help to solve the issue.

CC Scott.G who owns this libtool enhancement.

Thanks,
Dongxiao