use swSignalHander instead of __sighandler_t

[robberphex]

failed at php:7.0-cli-alpine.

Dockerfile:

FROM php:7.0-cli-alpine

RUN apk --no-cache add curl-dev
RUN docker-php-ext-install sockets

RUN curl -fsSL https://github.com/youzan/zan/archive/master.tar.gz -o zan.tar.gz && \
    mkdir /tmp/zan -p && tar -xf zan.tar.gz -C /tmp/zan --strip-components=1 && rm zan.tar.gz && \
    /usr/local/bin/docker-php-ext-configure /tmp/zan/zan-extension/ --enable-openssl && \
    docker-php-ext-install /tmp/zan/zan-extension/ && \
    rm -rf /tmp/zan/

build log:

...
cc -I. -I/tmp/zan/zan-extension -DPHP_ATOM_INC -I/tmp/zan/zan-extension/include -I/tmp/zan/zan-extension/main -I/tmp/zan/zan-extension -I/usr/local/include/php -I/usr/local/include/php/main -I/usr/local/include/php/TSRM -I/usr/local/include/php/Zend -I/usr/local/include/php/ext -I/usr/local/include/php/ext/date/lib -I/tmp/zan/zan-extension/include -fstack-protector-strong -fpic -fpie -O2 -DHAVE_CONFIG_H -Wall -fstack-protector-strong -fpic -fpie -O2 -std=gnu99 -fbounds-check -pthread -fstack-check -fstack-protector -fstack-protector-all -fno-strict-aliasing -c /tmp/zan/zan-extension/src/dns/DNS.c  -fPIC -DPIC -o src/dns/.libs/DNS.o
/bin/sh /tmp/zan/zan-extension/libtool --mode=compile cc  -I. -I/tmp/zan/zan-extension -DPHP_ATOM_INC -I/tmp/zan/zan-extension/include -I/tmp/zan/zan-extension/main -I/tmp/zan/zan-extension -I/usr/local/include/php -I/usr/local/include/php/main -I/usr/local/include/php/TSRM -I/usr/local/include/php/Zend -I/usr/local/include/php/ext -I/usr/local/include/php/ext/date/lib -I/tmp/zan/zan-extension/include  -fstack-protector-strong -fpic -fpie -O2 -DHAVE_CONFIG_H  -Wall -fstack-protector-strong -fpic -fpie -O2 -std=gnu99 -fbounds-check -pthread -fstack-check -fstack-protector -fstack-protector-all -fno-strict-aliasing   -c /tmp/zan/zan-extension/src/signal/Signal.c -o src/signal/Signal.lo 
mkdir src/signal/.libs
 cc -I. -I/tmp/zan/zan-extension -DPHP_ATOM_INC -I/tmp/zan/zan-extension/include -I/tmp/zan/zan-extension/main -I/tmp/zan/zan-extension -I/usr/local/include/php -I/usr/local/include/php/main -I/usr/local/include/php/TSRM -I/usr/local/include/php/Zend -I/usr/local/include/php/ext -I/usr/local/include/php/ext/date/lib -I/tmp/zan/zan-extension/include -fstack-protector-strong -fpic -fpie -O2 -DHAVE_CONFIG_H -Wall -fstack-protector-strong -fpic -fpie -O2 -std=gnu99 -fbounds-check -pthread -fstack-check -fstack-protector -fstack-protector-all -fno-strict-aliasing -c /tmp/zan/zan-extension/src/signal/Signal.c  -fPIC -DPIC -o src/signal/.libs/Signal.o
/tmp/zan/zan-extension/src/signal/Signal.c:28:39: error: unknown type name '__sighandler_t'
 static void swSignalfd_set(int signo, __sighandler_t callback);
                                       ^
/tmp/zan/zan-extension/src/signal/Signal.c: In function 'swSignal_add':
/tmp/zan/zan-extension/src/signal/Signal.c:104:9: warning: implicit declaration of function 'swSignalfd_set' [-Wimplicit-function-declaration]
         swSignalfd_set(signo, func);
         ^
/tmp/zan/zan-extension/src/signal/Signal.c: At top level:
/tmp/zan/zan-extension/src/signal/Signal.c:175:39: error: unknown type name '__sighandler_t'
 static void swSignalfd_set(int signo, __sighandler_t callback)
                                       ^
Makefile:324: recipe for target 'src/signal/Signal.lo' failed
make: *** [src/signal/Signal.lo] Error 1
The command '/bin/sh -c curl -fsSL https://github.com/youzan/zan/archive/master.tar.gz -o zan.tar.gz &&     mkdir /tmp/zan -p && tar -xf zan.tar.gz -C /tmp/zan --strip-components=1 && rm zan.tar.gz &&     /usr/local/bin/docker-php-ext-configure /tmp/zan/zan-extension/ --enable-openssl &&     docker-php-ext-install /tmp/zan/zan-extension/ &&     rm -rf /tmp/zan/' returned a non-zero code: 2
...

---

ref: https://gist.github.com/RobberPhex/26f92750c855e3ec2a39033821894611