cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration stdlib/secure_getenv.c -o stdlib/secure_getenv -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
stdlib/secure_getenv.c:12:22: error: call to undeclared function 'secure_getenv'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   12 |         const char* value = secure_getenv("FOO");
      |                             ^
stdlib/secure_getenv.c:12:14: error: incompatible integer to pointer conversion initializing 'const char *' with an expression of type 'int' [-Wint-conversion]
   12 |         const char* value = secure_getenv("FOO");
      |                     ^       ~~~~~~~~~~~~~~~~~~~~
2 errors generated.