fix build for ubuntu

BUILDING.md

@@ -79,13 +79,21 @@ So these are the wonky, unautomated steps to build the mac bundle:
 
 - Install Lua 5.2
 
-  ```sh
-  curl -R -O http://www.lua.org/ftp/lua-5.2.0.tar.gz
-  tar zxf lua-5.2.0.tar.gz
-  cd lua-5.2.0
-  make linux test
-  sudo make install
-  ```
+  - On Debian or Ubuntu:
+
+    ```sh
+    sudo apt-get install liblua5.2-dev
+    ```
+
+  - Otherwise install from source:
+
+    ```sh
+    curl -R -O http://www.lua.org/ftp/lua-5.2.0.tar.gz
+    tar zxf lua-5.2.0.tar.gz
+    cd lua-5.2.0
+    make linux test
+    sudo make install
+    ```
 
 - Install SDL 2
 

engine/Makefile

@@ -827,9 +827,19 @@ endif
 ifeq ($(TARGET_OS),UNIX)
 COMMON_CPPFLAGS += -DELF
 COMMON_OBJS += net_udp.o sys_unix.o
-COMMON_LIBS += m lua
+COMMON_LIBS += m
 NQCL_OBJS   += net_bsd.o
 
+# workaround for Blinky issue 74: https://github.com/shaunlebron/blinky/issues/74
+# We seem to have to use lua5.2 library in debian.
+IS_DEBIAN = $(shell test -f /etc/debian-version && echo "Y" || echo "N")
+ifeq ($(IS_DEBIAN),Y)
+COMMON_CPPFLAGS += $(shell pkg-config --cflags lua5.2)
+COMMON_LIBS += lua5.2
+else
+COMMON_LIBS += lua
+endif
+
 # FIXME - stupid hack
 ifeq ($(APP_BUNDLE),Y)
 COMMON_CPPFLAGS += -Dmain=SDL_main