Fix GH-8142: Compilation error on cygwin

* pcntl: SIGPOLL/si_band is unsupported
* intl: enable the signal apis with `_POSIX_C_SOURCE`

Closes GH-8146.

Author: devnexen

NEWS

@@ -2,6 +2,12 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? 2022, PHP 8.0.18
 
+- Intl:
+  . Fixed bug GH-8142 (Compilation error on cygwin). (David Carlier)
+
+- Pcntl:
+  . Fixed bug GH-8142 (Compilation error on cygwin). (David Carlier)
+
 - Standard:
   . Fixed bug GH-8048 (Force macOS to use statfs). (risner)
 

ext/intl/config.m4

@@ -85,6 +85,9 @@ if test "$PHP_INTL" != "no"; then
   PHP_REQUIRE_CXX()
   PHP_CXX_COMPILE_STDCXX(11, mandatory, PHP_INTL_STDCXX)
   PHP_INTL_CXX_FLAGS="$INTL_COMMON_FLAGS $PHP_INTL_STDCXX $ICU_CXXFLAGS"
+  case $host_alias in
+  *cygwin*) PHP_INTL_CXX_FLAGS="$PHP_INTL_CXX_FLAGS -D_POSIX_C_SOURCE=200809L"
+  esac
   if test "$ext_shared" = "no"; then
     PHP_ADD_SOURCES(PHP_EXT_DIR(intl), $PHP_INTL_CXX_SOURCES, $PHP_INTL_CXX_FLAGS)
   else

ext/pcntl/pcntl.c

@@ -1160,7 +1160,7 @@ static void pcntl_siginfo_to_zval(int signo, siginfo_t *siginfo, zval *user_sigi
 			case SIGBUS:
 				add_assoc_double_ex(user_siginfo, "addr", sizeof("addr")-1, (zend_long)siginfo->si_addr);
 				break;
-#ifdef SIGPOLL
+#if defined(SIGPOLL) && !defined(__CYGWIN__)
 			case SIGPOLL:
 				add_assoc_long_ex(user_siginfo, "band", sizeof("band")-1, siginfo->si_band);
 # ifdef si_fd