Support build with disabled zend signals (#2886)

I seem to have taken care about the globals, but missed zend_signal_handler_unblock.

Signed-off-by: Bob Weinand <bob.weinand@datadoghq.com>

dockerfiles/verify_packages/Makefile

@@ -128,6 +128,11 @@ test_alpine_install_no_ext_curl_yes_curl_cli.sh \
 	@echo "################### $(@) ###################"
 	docker run --rm -ti -v $(shell pwd)/../../:/app --env-file $(shell pwd)/.env -e CIRCLECI --workdir=/app alpine:3.13 sh dockerfiles/verify_packages/installer/$(@)
 
+test_alpine_zts_no_zend_signals.sh \
+	: global_test_dependencies
+	@echo "################### $(@) ###################"
+	docker run --rm -ti -v $(shell pwd)/../../:/app --env-file $(shell pwd)/.env -e CIRCLECI --workdir=/app dunglas/frankenphp:php8.3.12-alpine sh dockerfiles/verify_packages/installer/$(@)
+
 test_alpine_no_libexecinfo.sh: global_test_dependencies
 	@echo "################### $(@) ###################"
 	docker run --rm -ti -v $(shell pwd)/../../:/app --env-file $(shell pwd)/.env -e CIRCLECI --workdir=/app php:7.4-cli-alpine sh dockerfiles/verify_packages/installer/$(@)

dockerfiles/verify_packages/installer/test_alpine_zts_no_zend_signals.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env sh
+
+set -e
+
+. "$(dirname ${0})/utils.sh"
+
+apk add libgcc
+
+# Initially no ddtrace
+assert_no_ddtrace
+
+# Install using the php installer
+version=$(cat VERSION)
+php ./build/packages/datadog-setup.php --enable-profiling --php-bin php
+assert_ddtrace_version "${version}"
+assert_profiler_version "${version}"
+assert_appsec_version "${version}"
+
+assert_sources_path_exists

ext/threads.c

@@ -1,9 +1,11 @@
 #include "threads.h"
 #define zend_signal_globals_id zend_signal_globals_id_dummy
 #define zend_signal_globals_offset zend_signal_globals_offset_dummy
+#define zend_signal_handler_unblock zend_signal_handler_unblock_dummy
 #include <Zend/zend.h>
 #undef zend_signal_globals_id
 #undef zend_signal_globals_offset
+#undef zend_signal_handler_unblock
 #include "ddtrace.h"
 
 #if ZTS
@@ -18,6 +20,8 @@ extern __attribute__((weak, weak_import)) size_t zend_signal_globals_offset;
 __attribute__((weak)) int zend_signal_globals_id;
 __attribute__((weak)) size_t zend_signal_globals_offset;
 #endif
+
+__attribute__((weak)) void zend_signal_handler_unblock(void);
 #endif
 
 HashTable ddtrace_tls_bases; // map thread id to TSRMLS_CACHE