Merge branch 'signal-h' into 'master'

Fix signal.h include headers

See merge request redox-os/relibc!1190

src/header/signal/cbindgen.toml

@@ -6,7 +6,7 @@
 # - "pid_t As described in <sys/types.h>."
 # - "The <signal.h> header shall define the pthread_attr_t type as described in <sys/types.h>."
 # - "Inclusion of the <signal.h> header may make visible all symbols from the <time.h> header."
-sys_includes = ["sys/types.h"]
+sys_includes = ["sys/types.h", "stdint.h"]
 include_guard = "_RELIBC_SIGNAL_H"
 after_includes = """
 #include <bits/timespec.h> // for timespec from time.h