gettop: fix symlink detection

Summary: We must use the -P flag for pwd to properly get $PWD from the environment *with* symlinks. Otherwise symlink
detection is broken and anything we do using $(gettop) at the top of a symlinked path won't work properly. I noticed this
issue while running on a system that has a SSD RAID symlinked to my android build home directory, which is ~/ssd_storage.
The top in this instance is a symlink, which means that gettop() returns my home path, or the path above the symlink
directory (but not the symlinked directory). This is a major issue in case developers choose to use $(gettop),
$ANDROID_BUILD_TOP, or $T (doesn't really matter either way).

Test Plan: Create a symlink and sync android source into the path. Open up the symlink, run envsetup.sh, and check
$(gettop) output.

While this isn't the best solution, it fixes an issue without creating new issues.

Change-Id: I65bc345753805e6161098d2af6e0bee0b07d37b1
Fix incorrect x86 build rules.

combo/TARGET_x86*.mk mistakenly added TARGET_GLOBAL_CFLAGS to their
linker command lines. This results in clang builds not working properly,
since they strip some unknown flags from TARGET_GLOBAL_CFLAGS.

Change-Id: I60a1ff5df70305323134435e4ae107ea7acfe8ea
Merge "Fix incorrect x86 build rules."
Merge "gettop: fix symlink detection"
add jsr166 tests to cts.
Bug: 10390711

Change-Id: I512770e98f61995fc33043d35562dc3b213a4930
Adding apache-harmony to cts.

(cherry-picked from commit 5fef52e9c986184796ff1e5fe54390614ba318a6)

Change-Id: I9a6595f5e8bc30654a062e0917d3ecd3ba28ebc7
changing the rules following java package renaming for
external/apache-harmony.

(cherry picked from commit 27b4b5ffe12b179fc0d24747f9ead2d5f52c871a)

Change-Id: Ia5a7b2d401f23dfdc556ef1982efd441ed1d1ae2
Fix up android.core CTS tests.

Fix several wrongly configured tests that were either
looking for tests in the wrong jar (apache-harmony-tests
instead of core-tests) or using the wrong prefix.

Also, this change creates subsets of the harmony tests based
on subpackage names (java.net, java.io, java.nio etc.) instead
of the earlier harmony groupings.

Change-Id: Iea0e20d23512611d1aac92b2f8219031b6396c77
Merge "add jsr166 tests to cts. Bug: 10390711"
Merge "Adding apache-harmony to cts."
Merge "changing the rules following java package renaming for external/apache-harmony."
Merge "Fix up android.core CTS tests."
Merge branch 'master' of https://android.googlesource.com/platform/build into HEAD