5.7.3.4 Asm Option
The -fasm option reserves the use of
asm, inline and typeof as
keywords, preventing them from being defined as identifiers. This is the default action
if no option is specified.
The -fno-asm form of this option restricts the recognition of these
keywords. You can, instead, use the keywords __asm__,
__inline__ and __typeof__, which have identical
meanings.
The -ansi option implies -fno-asm.