Instead of printing the same message over and over again, if a target can't use
a specific sanitizer, the message will be printed only once for the first
affected target now.
In some special cases static linking the sanitizers won't work, and you have to
preload libasan. To find the right libasan depending on the application to be
executed, a wrapper script was added. The location of the wrapper script can be
accessed via ASan_WRAPPER variable.
If you like to preload a sanitized library in front of an application, it will
fail, because it is not the first in the library list anymore. This behaviour
is gcc specific - clang will static link the sanitizers instead. To get the
same for gcc, the new SANITIZE_LINK_STATIC flag will link the sanitizers
static in gcc environments.
Note: The preloaded executable must be sanitized, too! Otherwise ASan will
print an error message!
* Added a new module FindSanitizers with new function add_sanitizers to combine
all sanitizers in one function instead of adding each one by one.
* Code of FindASan.cmake was outdourced into helper functions, so that the code
may be used by other sanitizer modules, too.
* AddressSanitizer will be used with -O1 now to get a better performance.
* removed build type ASAN. Targets should define ASan usage by sanitize_address
function
* compiler flags will be searched by compiler instead of per language
* FindASan warns, if a target can't be sanitized because of incompatible
compilers
* added some helper functions
