Fix warnings

This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.

libc/calls/struct/filter.internal.h

@@ -15,7 +15,7 @@ struct sock_filter {
 
 struct sock_fprog {
   unsigned short len;
-  struct sock_filter *filter;
+  const struct sock_filter *filter;
 };
 
 #define BPF_RVAL(code)   ((code)&0x18)

libc/calls/struct/iovec.internal.h

@@ -21,7 +21,7 @@ ssize_t sys_writev_metal(struct Fd *, const struct iovec *, int);
 ssize_t sys_writev_nt(int, const struct iovec *, int);
 ssize_t sys_writev_serial(struct Fd *, const struct iovec *, int);
 ssize_t sys_send_nt(int, const struct iovec *, size_t, uint32_t);
-ssize_t sys_sendto_nt(int, const struct iovec *, size_t, uint32_t, void *,
+ssize_t sys_sendto_nt(int, const struct iovec *, size_t, uint32_t, const void *,
                       uint32_t);
 
 const char *DescribeIovec(char[300], ssize_t, const struct iovec *, int);

libc/calls/struct/termios.internal.h

@@ -5,7 +5,7 @@
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
 
-const char *DescribeTermios(char[1024], ssize_t, struct termios *);
+const char *DescribeTermios(char[1024], ssize_t, const struct termios *);
 
 #define DescribeTermios(rc, tio) DescribeTermios(alloca(1024), rc, tio)
 

libc/calls/struct/timespec.h

@@ -45,7 +45,7 @@ static inline bool timespec_iszero(struct timespec __ts) {
   return !(__ts.tv_sec | __ts.tv_nsec);
 }
 static inline bool timespec_isvalid(struct timespec __ts) {
-  return __ts.tv_sec >= 0 && __ts.tv_nsec < 1000000000ull;
+  return __ts.tv_sec >= 0 && __ts.tv_nsec + 0ull < 1000000000ull;
 }
 #endif /* _COSMO_SOURCE */
 

libc/calls/struct/timeval.h

@@ -42,7 +42,7 @@ static inline bool timeval_iszero(struct timeval __tv) {
   return !(__tv.tv_sec | __tv.tv_usec);
 }
 static inline bool timeval_isvalid(struct timeval __tv) {
-  return __tv.tv_sec >= 0 && __tv.tv_usec < 1000000ull;
+  return __tv.tv_sec >= 0 && __tv.tv_usec + 0ull < 1000000ull;
 }
 #endif /* _COSMO_SOURCE */
 

libc/calls/struct/winsize.internal.h

@@ -7,7 +7,7 @@
 COSMOPOLITAN_C_START_
 
 int tcgetwinsize_nt(int, struct winsize *);
-const char *DescribeWinsize(char[64], int, struct winsize *);
+const char *DescribeWinsize(char[64], int, const struct winsize *);
 #define DescribeWinsize(rc, ws) DescribeWinsize(alloca(64), rc, ws)
 
 COSMOPOLITAN_C_END_