refactor headers, especially alltypes.h, and improve C++ ABI compat

the arch-specific bits/alltypes.h.sh has been replaced with a generic
alltypes.h.in and minimal arch-specific bits/alltypes.h.in.

this commit is intended to have no functional changes except:
- exposing additional symbols that POSIX allows but does not require
- changing the C++ name mangling for some types
- fixing the signedness of blksize_t on powerpc (POSIX requires signed)
- fixing the limit macros for sig_atomic_t on x86_64
- making dev_t an unsigned type (ABI matching goal, and more logical)

in addition, some types that were wrongly defined with long on 32-bit
archs were changed to int, and vice versa; this change is
non-functional except for the possibility of making pointer types
mismatch, and only affects programs that were using them incorrectly,
and only at build-time, not runtime.

the following changes were made in the interest of moving
non-arch-specific types out of the alltypes system and into the
headers they're associated with, and also will tend to improve
application compatibility:
- netdb.h now includes netinet/in.h (for socklen_t and uint32_t)
- netinet/in.h now includes sys/socket.h and inttypes.h
- sys/resource.h now includes sys/time.h (for struct timeval)
- sys/wait.h now includes signal.h (for siginfo_t)
- langinfo.h now includes nl_types.h (for nl_item)

for the types in stdint.h:
- types which are of no interest to other headers were moved out of
  the alltypes system.
- fast types for 8- and 64-bit are hard-coded (at least for now); only
  the 16- and 32-bit ones have reason to vary by arch.

and the following types have been changed for C++ ABI purposes;
- mbstate_t now has a struct tag, __mbstate_t
- FILE's struct tag has been changed to _IO_FILE
- DIR's struct tag has been changed to __dirstream
- locale_t's struct tag has been changed to __locale_struct
- pthread_t is defined as unsigned long in C++ mode only
- fpos_t now has a struct tag, _G_fpos64_t
- fsid_t's struct tag has been changed to __fsid_t
- idtype_t has been made an enum type (also required by POSIX)
- nl_catd has been changed from long to void *
- siginfo_t's struct tag has been removed
- sigset_t's has been given a struct tag, __sigset_t
- stack_t has been given a struct tag, sigaltstack
- suseconds_t has been changed to long on 32-bit archs
- [u]intptr_t have been changed from long to int rank on 32-bit archs
- dev_t has been made unsigned

summary of tests that have been performed against these changes:
- nsz's libc-test (diff -u before and after)
- C++ ABI check symbol dump (diff -u before, after, glibc)
- grepped for __NEED, made sure types needed are still in alltypes
- built gcc 3.4.6

include/signal.h

@@ -12,7 +12,6 @@ extern "C" {
  || defined(_BSD_SOURCE)
 
 #ifdef _GNU_SOURCE
-#define __siginfo siginfo
 #define __ucontext ucontext
 #endif
 
@@ -25,7 +24,6 @@ extern "C" {
 #define __NEED_time_t
 #define __NEED_clock_t
 #define __NEED_sigset_t
-#define __NEED_siginfo_t
 
 #include <bits/alltypes.h>
 
@@ -77,19 +75,7 @@ extern "C" {
 #define CLD_STOPPED 5
 #define CLD_CONTINUED 6
 
-struct sigaction {
-	union {
-		void (*sa_handler)(int);
-		void (*sa_sigaction)(int, siginfo_t *, void *);
-	} __sa_handler;
-	sigset_t sa_mask;
-	int sa_flags;
-	void (*sa_restorer)(void);	
-};
-#define sa_handler   __sa_handler.sa_handler
-#define sa_sigaction __sa_handler.sa_sigaction
-
-typedef struct {
+typedef struct sigaltstack {
 	void *ss_sp;
 	int ss_flags;
 	size_t ss_size;
@@ -100,7 +86,7 @@ union sigval {
 	void *sival_ptr;
 };
 
-struct __siginfo {
+typedef struct {
 	int si_signo, si_errno, si_code;
 	union {
 		char __pad[128 - 2*sizeof(int) - sizeof(long)];
@@ -126,7 +112,7 @@ struct __siginfo {
 			int si_fd;
 		} __sigpoll;
 	} __si_fields;
-};
+} siginfo_t;
 #define si_pid     __si_fields.__sigchld.si_pid
 #define si_uid     __si_fields.__sigchld.si_uid
 #define si_status  __si_fields.__sigchld.si_status
@@ -141,6 +127,18 @@ struct __siginfo {
 #define si_ptr     __si_fields.__rt.si_sigval.sival_ptr
 #define si_int     __si_fields.__rt.si_sigval.sival_int
 
+struct sigaction {
+	union {
+		void (*sa_handler)(int);
+		void (*sa_sigaction)(int, siginfo_t *, void *);
+	} __sa_handler;
+	sigset_t sa_mask;
+	int sa_flags;
+	void (*sa_restorer)(void);	
+};
+#define sa_handler   __sa_handler.sa_handler
+#define sa_sigaction __sa_handler.sa_sigaction
+
 struct sigevent {
 	union sigval sigev_value;
 	int sigev_signo;