automatically set proxy for pear/pecl (#692)

* automatically set proxy for pear/pecl

* only set once

* fix shell code style

* fix possibly unset vars

install-php-extensions

@@ -3712,6 +3712,13 @@ configureInstaller() {
 		done
 	fi
 	if test $USE_PICKLE -eq 0; then
+		if test -z "$(pear config-get http_proxy)"; then
+			if test -n "${http_proxy:-}"; then
+				pear config-set http_proxy "$http_proxy" || true
+			elif test -n "${HTTP_PROXY:-}"; then
+				pear config-set http_proxy "$HTTP_PROXY" || true
+			fi
+		fi
 		pecl channel-update pecl.php.net || true
 	fi
 }