Capture error message when building C files

Add a new exception `CompileError` to differtiate that the exception raised
during the compilation.

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>

scripts/mbedtls_framework/c_build_helper.py

@@ -11,6 +11,15 @@
 import sys
 import tempfile
 
+class CompileError(Exception):
+    """Excetion to represent an error during the compilation."""
+
+    def __init__(self, message):
+        """Save the error massage"""
+
+        super().__init__()
+        self.message = message
+
 def remove_file_if_exists(filename):
     """Remove the specified file, ignoring errors."""
     if not filename:
@@ -107,7 +116,13 @@ def compile_c_file(c_filename, exe_filename, include_dirs):
     else:
         cmd += ['-o' + exe_filename]
 
-    subprocess.check_call(cmd + [c_filename])
+    try:
+        subprocess.check_output(cmd + [c_filename],
+                                stderr=subprocess.PIPE,
+                                universal_newlines=True)
+
+    except subprocess.CalledProcessError as e:
+        raise CompileError(e.stderr) from e
 
 def get_c_expression_values(
         cast_to, printf_format,