Description:
------------
Configure is not able to detect asm/signal.h any more. This problem started to occur in PHP 4.3.4 with several of my Debian boxes.

Compilation failes with the following error:

/bin/sh /usr/src/php-4.3.4/libtool --silent --preserve-dup-deps --mode=compile gcc  -Iext/mysql/ -I/usr/src/php-4.3.4/ext/mysql/ -DPHP_ATOM_INC -I/usr/src/php-4.3.4/include -I/usr/src/php-4.3.4/main -I/usr/src/php-4.3.4 -I/usr/src/php-4.3.4/Zend -I/usr/include/libxml2 -I/usr/src/FDFToolkitForUNIX/HeadersAndLibraries/headers -I/usr/X11R6/include -I/usr/include/freetype2 -I/usr/include/c-client -I/usr/src/php-4.3.4/ext/mbstring/mbregex -I/usr/src/php-4.3.4/ext/mbstring/libmbfl -I/usr/src/php-4.3.4/ext/mbstring/libmbfl/mbfl -I/usr/include/mysql  -I/usr/src/php-4.3.4/TSRM  -g -O2  -prefer-pic -c /usr/src/php-4.3.4/ext/mysql/php_mysql.c -o ext/mysql/php_mysql.lo
/usr/src/php-4.3.4/ext/mysql/php_mysql.c: In function `_close_mysql_link':
/usr/src/php-4.3.4/ext/mysql/php_mysql.c:288: `SIGPIPE' undeclared (first use in this function)
/usr/src/php-4.3.4/ext/mysql/php_mysql.c:288: (Each undeclared identifier is reported only once
/usr/src/php-4.3.4/ext/mysql/php_mysql.c:288: for each function it appears in.)
/usr/src/php-4.3.4/ext/mysql/php_mysql.c:288: `SIG_IGN' undeclared (first use in this function)
/usr/src/php-4.3.4/ext/mysql/php_mysql.c:288: warning: assignment makes pointer from integer without a cast
/usr/src/php-4.3.4/ext/mysql/php_mysql.c: In function `_close_mysql_plink':
/usr/src/php-4.3.4/ext/mysql/php_mysql.c:303: `SIGPIPE' undeclared (first use in this function)
/usr/src/php-4.3.4/ext/mysql/php_mysql.c:303: `SIG_IGN' undeclared (first use in this function)
/usr/src/php-4.3.4/ext/mysql/php_mysql.c:303: warning: assignment makes pointer from integer without a cast
make: *** [ext/mysql/php_mysql.lo] Error 1


Reproduce code:
---------------
My configure call:

'./configure' '--prefix=/usr' '--with-apxs=/usr/bin/apxs' '--with-regex=php' '--with-config-file-path=/etc/php4/apache' '--disable-rpath' '--disable-debug' '--enable-memory-limit' '--with-layout=GNU' '--enable-calendar' '--enable-sysvsem' '--enable-sysvshm' '--enable-track-vars' '--enable-trans-sid' '--enable-bcmath' '--with-bz2' '--enable-ctype' '--with-db2' '--with-iconv' '--enable-exif' '--enable-filepro' '--enable-ftp' '--with-gettext' '--enable-mbstring' '--with-pcre-regex' '--enable-shmop' '--enable-sockets' '--enable-wddx' '--disable-xml' '--with-expat-dir=/usr' '--enable-yp' '--with-zlib' '--without-pgsql' '--with-openssl=/usr' '--disable-static' '--with-dom=/usr' '--with-zlib-dir=/usr' '--with-gd' '--with-jpeg-dir=/usr' '--with-png-dir=/usr' '--with-freetype-dir=/usr' '--with-imap=/usr' '--with-mhash=/usr' '--with-mm' '--with-mysql=/usr' '--with-recode=/usr' '--with-ttf=/usr' '--with-t1lib=/usr' --with-pdflib --with-fdftk=../FDFToolkitForUNIX --with-xpm-dir=/usr --with-curl


Actual result:
--------------
configure outputs "signal.h not detected" and in main/php_config.h the line #define HAVE_SIGNAL_H is commented out.