i#4291: append to LD_PRELOAD when using -late

[mattgreen]

When using -late, append to LD_PRELOAD rather than overwrite it.

Fixes #4291

[derekbruening]

Thank you for the patch.

[derekbruening]

run arm tests

[derekbruening]

Travis is misbehaving: their Mac bots are dying or sthg midway through our build. Will try one more rerun.

[derekbruening]

So it is in fact a build failure on Mac. It is not presented very well which is #4223.

/Users/travis/build/DynamoRIO/dynamorio/core/unix/injector.c:221:17: error: unused variable 'ld_preload' [-Werror,-Wunused-variable]
    const char *ld_preload = NULL;
                ^
Users/travis/build/DynamoRIO/dynamorio/core/unix/injector.c:223:17: error: unused variable 'cur_preload' [-Werror,-Wunused-variable]
    const char *cur_preload = getenv("LD_PRELOAD");
                ^
/Users/travis/build/DynamoRIO/dynamorio/core/unix/injector.c:222:17: error: unused variable 'dr_ld_preload_libs' [-Werror,-Wunused-variable]
    const char *dr_ld_preload_libs = "libdynamorio.so libdrpreload.so";
                ^
/Users/travis/build/DynamoRIO/dynamorio/core/unix/injector.c:216:10: error: unused variable 'ld_preload_libs' [-Werror,-Wunused-variable]
    char ld_preload_libs[MAX_OPTIONS_STRING];

@mattgreen, If you could fix the build failure.

[mattgreen]

Hmm, Windows build failed. I'm surprised by that considering the source file isn't in the build. Is there a way to re-run it?

[derekbruening]

Hmm, Windows build failed. I'm surprised by that considering the source file isn't in the build. Is there a way to re-run it?

Looks like drwrap-test 32-bit: #4231. Yes it can be re-run individually but I'll update the branch which is another way to re-run.

[derekbruening]

run arm tests

[derekbruening]

Just documenting that we're going to live without a test for the new code.

[mattgreen]

Thanks for the feedback and accepting it!