[Feature request] Support for using more than one compiler in a build

[csullivan]

It would be wonderful if there was a way to specify a different compiler for compiling objects from sources with a specific extension. For example

CUSTOM_COMPILER = nvcc (NVIDIA CUDA compiler)
CUSTOM_SOURCE_EXT = .cu
CUSTOM_COMPILER_FLAGS = ...
CUSTOM_COMPILER_LINK_FLAGS = ...
etc.

with the resulting object files being treated in the same manner as all other files, being linked in to executables and libraries as necessary. As it is, I have a separate makefile, which MagicMake calls first to compile the "custom" objects, and then they are explicitly listed in EXTERNAL_STATIC_OBJECTS. This becomes more of an issue when the two types of sources have mutual dependencies.

[csullivan]

Perhaps a better example would be

CUSTOM_COMPILER = gfortran
CUSTOM_SOURCE_EXT = .f90
CUSTOM_COMPILER_FLAGS = ...
CUSTOM_COMPILER_LINK_FLAGS = ...

where the fortran source doesn't include any modules, just plain source files that are compiled directly to objects, and there would be some c/c++ code that calls the gfortran mangled functions.