I use Mageia 6 with Lazarus 1.8.2. I used Pierre Muller's four .o files to overwrite those in the rtl subfolder to successfully remove the "crtbeginS.o not found, this will probably cause a linking error" warnings - the first of two similar warnings.
That's silly. To remove the crtbegin/end warnings you should include the path to the current GCC lib files. That's all. It does not need any patches. And the warning is harmless in most cases.
E.g.:
-Fl/usr/lib/gcc/arm-linux-gnueabihf/6.3.0
This path may differ on Mageia but it is there.
Alternatively find out where your current GCC is (whereis GCC && gcc --version), match it to the ./lib with the same version and export GCCLIBDIR=<that path> as an environment variable.
Second alternative: FPC supports GCCLIBDIR=<that path> as a makefile setting, but that is for the compiler and rtl only.
Third (best option) include it in /etc/fpc.cfg as -Fl option'. If you use multiple fpc.cfg's with different paths, include it in all of them.
Hey, presto: warnings are gone....