리눅스환경에서 컴파일하는데 Invalid option 'preferred stack boundary=2' 의 의미가 뭔가요?

혹시 -mpreferred-stack-boundary=num 이거 아닐까요?
gcc manpage에 보면 i386 옵션 부분에 있는 겁니다. 참조하세요.

----- man page ----------
-mpreferred-stack-boundary=num
Attempt to keep the stack boundary aligned to a 2 raised to num byte boundary. If -mpre-
ferred-stack-boundary is not specified, the default is 4 (16 bytes or 128 bits), except when optimizing
for code size (-Os), in which case the default is the minimum correct alignment (4 bytes for x86, and 8
bytes for x86-64).

On Pentium and PentiumPro, "double" and "long double" values should be aligned to an 8 byte boundary (see
-malign-double) or suffer significant run time performance penalties. On Pentium III, the Streaming SIMD
Extension (SSE) data type "__m128" suffers similar penalties if it is not 16 byte aligned.

To ensure proper alignment of this values on the stack, the stack boundary must be as aligned as that
required by any value stored on the stack. Further, every function must be generated such that it keeps
the stack aligned. Thus calling a function compiled with a higher preferred stack boundary from a func-
tion compiled with a lower preferred stack boundary will most likely misalign the stack. It is recom-
mended that libraries that use callbacks always use the default setting.

This extra alignment does consume extra stack space, and generally increases code size. Code that is sen-
sitive to stack space usage, such as embedded systems and operating system kernels, may want to reduce the
preferred alignment to -mpreferred-stack-boundary=2.