Description of problem:
Orbit-idl uses a compiler to preprocess idl file. This idl file can contain #include 
directives. If header file pointed in the include directive is missed the compiler 
emits an error and changes its exit status to non-zero. GNU compiler doesnât stop 
working at this and continues preprocessing the rest of the main source file. Thatâs 
only its behavior and the output after the error is quite unreliable. However orbit-idl 
doesnât check compiler output status and the error presence and continues to 
process the output. Donât you think it is too bizarre to go on in the presence of 
errors? If there is a missed header file, the errors probably will appear during the 
build stage where source files use orbit-idl generated header and ultimately an 
user will be frustrated by the incomprehensible errors (like unknown identifier used, 
but not defined anywhere!). Orbit-idl should prevent these situations and report 
about the problem timely. Nowadays there is no any diagnostics at all if .idl file 
includes missed header file.

As another reason to check for compiler errors, you can imagine that not all 
compilers continue working after error is spotted; Intel compiler is the case. In 
such a case the header produced by orbit-idl is incomplete and cannot be used 
properly.


Version-Release number of selected component (if applicable):


How reproducible:
always

Steps to Reproduce:
1. Compose an idl file (test.idl):
struct One {
    long i;
};

#include <inexisting.h>

struct Two {
    long j;
};

2. Try `orbit-idl test.idl`
    
Actual results:
No any diagnostics, error is suppressed, output files are produced.

Expected results:
Error or at least warning about missing file. A Developer or an user spot it and fix 
the .idl file accordingly.

Additional info: