參考資訊：
https://github.com/u-boot/u-boot/commit/2b9912e6a7df7b1f60beb7942bd0e6fa5f9d0167
問題如下：
$ gcc -g -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer -idirafter uboot/include -idirafter uboot/include2 -idirafter uboot/include -I uboot/lib/libfdt -I uboot/tools -DCONFIG_SYS_TEXT_BASE=0xE00000 -DUSE_HOSTCC -D__KERNEL_STRICT_NAMES -pedantic -c -o sha1.o uboot/lib/sha1.c
uboot/lib/sha1.c:64:19: error: unknown type name ‘sha1_context’
64 | void sha1_starts (sha1_context * ctx)
| ^~~~~~~~~~~~
uboot/lib/sha1.c:76:26: error: unknown type name ‘sha1_context’
76 | static void sha1_process(sha1_context *ctx, const unsigned char data[64])
| ^~~~~~~~~~~~
uboot/lib/sha1.c:233:18: error: unknown type name ‘sha1_context’
233 | void sha1_update(sha1_context *ctx, const unsigned char *input,
| ^~~~~~~~~~~~
uboot/lib/sha1.c:280:19: error: unknown type name ‘sha1_context’
280 | void sha1_finish (sha1_context * ctx, unsigned char output[20])
| ^~~~~~~~~~~~
uboot/lib/sha1.c: In function ‘sha1_csum’:
uboot/lib/sha1.c:312:9: error: unknown type name ‘sha1_context’
312 | sha1_context ctx;
| ^~~~~~~~~~~~
uboot/lib/sha1.c:314:9: warning: implicit declaration of function ‘sha1_starts’ [-Wimplicit-function-declaration]
314 | sha1_starts (&ctx);
| ^~~~~~~~~~~
uboot/lib/sha1.c:315:9: warning: implicit declaration of function ‘sha1_update’; did you mean ‘SHA1Update’? [-Wimplicit-function-declaration]
315 | sha1_update (&ctx, input, ilen);
| ^~~~~~~~~~~
| SHA1Update
uboot/lib/sha1.c:316:9: warning: implicit declaration of function ‘sha1_finish’ [-Wimplicit-function-declaration]
316 | sha1_finish (&ctx, output);
| ^~~~~~~~~~~
uboot/lib/sha1.c: In function ‘sha1_csum_wd’:
uboot/lib/sha1.c:326:9: error: unknown type name ‘sha1_context’
326 | sha1_context ctx;
| ^~~~~~~~~~~~
uboot/lib/sha1.c: In function ‘sha1_hmac’:
uboot/lib/sha1.c:360:9: error: unknown type name ‘sha1_context’
360 | sha1_context ctx;
| ^~~~~~~~~~~~
uboot/lib/sha1.c:389:34: error: ‘sha1_context’ undeclared (first use in this function)
389 | memset (&ctx, 0, sizeof (sha1_context));
| ^~~~~~~~~~~~
uboot/lib/sha1.c:389:34: note: each undeclared identifier is reported only once for each function it appears in
uboot/lib/sha1.c: At top level:
uboot/lib/sha1.c:392:19: warning: ‘_sha1_src’ defined but not used [-Wunused-const-variable=]
392 | static const char _sha1_src[] = "_sha1_src";
| ^~~~~~~~~
uboot/lib/sha1.c:270:28: warning: ‘sha1_padding’ defined but not used [-Wunused-const-variable=]
270 | static const unsigned char sha1_padding[64] = {
| ^~~~~~~~~~~~
make[1]: *** [Makefile:263: sha1.o] Error 1
make[1]: Leaving directory 'uboot/tools'
make: *** [Makefile:588: tools] Error 2
解法如下：
$ vim lib/sha1.c
39 #include "../include/sha1.h"