Validate that GNU compile options produce numerically-safe binaries

[kvrigor]

Related to #52 . The current set of GNU compiler flags needs to be scrutinized if they actually produce numerically-safe code.

eCLM/cmake/SetBuildOptions.cmake

Lines 24 to 31 in c9f3348

	if(COMPILER STREQUAL "GNU")
	add_compile_definitions(CPRGNU)
	set(CMAKE_C_FLAGS "-std=gnu99 -fopenmp")
	set(CMAKE_C_FLAGS_DEBUG "-fcheck=bounds")
	set(CMAKE_C_FLAGS_RELEASE "-O")
	set(CMAKE_Fortran_FLAGS "-fconvert=big-endian -ffree-line-length-none -ffixed-line-length-none -ffree-form -fopenmp -fallow-argument-mismatch")
	set(CMAKE_Fortran_FLAGS_DEBUG "-g -Wall -Og -fbacktrace -ffpe-trap=zero,overflow -fcheck=bounds")
	set(CMAKE_Fortran_FLAGS_RELEASE "-O")