cmake: fix pkg-config in static mode

Change-Id: Ic2397eee6ea67fc5d0b76ce77bbd8e000f90177c

CMakeLists.txt

@@ -37,7 +37,7 @@ if (NOT MSVC)
     set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE BOTH)
     list(APPEND CMAKE_PREFIX_PATH ${DEPENDENCIES_PATH})
     find_package (PkgConfig REQUIRED)
-    if(BUILD_STATIC)
+    if(NOT BUILD_SHARED_LIBS)
         list(APPEND PKG_CONFIG_EXECUTABLE "--static")
     endif()
 

Dockerfile

@@ -6,7 +6,7 @@ RUN apk add --no-cache \
         cppunit-dev gnutls-dev jsoncpp-dev \
         argon2-dev openssl-dev fmt-dev \
         http-parser-dev asio-dev msgpack-cxx-dev \
-        readline-dev
+        readline-dev yaml-cpp-dev libunistring-dev
 
 # Build restinio
 RUN mkdir restinio && cd restinio \