Fixes Android builds on Linux environments (#1530)

* simple_game: Configure Make and makefile for Linux environments

* simple_game: Fix build issues on Android plaform with Linux HOST

The Makefile.Android.linux file was out of date with the rest of the
project, so this commit updates the paths, as well as leaving some as
optional, if it is already configured as an environment variable.

In addition, it corrects the build error related to static raylib:
the makefile was trying to generate libmain.so using the path of the
NDK libraries, instead of using those of the Android system, which
resulted in crashes in the generated apk.

templates/simple_game/Makefile

@@ -101,6 +101,15 @@ ifeq ($(PLATFORM),PLATFORM_DRM)
         PLATFORM_OS=LINUX
     endif
 endif
+ifeq ($(PLATFORM),PLATFORM_ANDROID)
+    UNAMEOS=$(shell uname)
+    ifeq ($(UNAMEOS),Linux)
+        PLATFORM_OS=LINUX
+    endif
+    ifeq ($(UNAMEOS),Darwin)
+        PLATFORM_OS=OSX
+    endif
+endif
 
 # RAYLIB_PATH adjustment for different platforms.
 # If using GNU make, we can get the full path to the top of the tree. Windows? BSD?
@@ -388,6 +397,15 @@ OBJS = $(patsubst %.c, %.o, $(PROJECT_SOURCE_FILES))
 # For Android platform we call a custom Makefile.Android
 ifeq ($(PLATFORM),PLATFORM_ANDROID)
     MAKEFILE_PARAMS = -f Makefile.Android 
+    # For Linux and macOS set make and makefile
+    ifeq ($(PLATFORM_OS),LINUX)
+        MAKE = make
+        MAKEFILE_PARAMS = -f Makefile.Android.linux
+    endif
+    ifeq ($(PLATFORM_OS),OSX)
+        MAKE = make
+        MAKEFILE_PARAMS = -f Makefile.Android.macos
+    endif
     export PROJECT_NAME
     export PROJECT_SOURCE_FILES
 else

templates/simple_game/Makefile.Android.linux

@@ -28,7 +28,7 @@
 
 # Define required raylib variables
 PLATFORM               ?= PLATFORM_ANDROID
-RAYLIB_PATH            ?= $(HOME)/raylib_sources.ln
+RAYLIB_PATH            ?= ../../
 
 # Define Android architecture (armeabi-v7a, arm64-v8a, x86, x86-64) and API version
 ANDROID_ARCH           ?= ARM64
@@ -48,9 +48,9 @@ endif
 # no need to define JAVA_HOME , JAVA_BIN in linux environment (binaries are in $PATH)
 #JAVA_HOME              ?= C:/JavaJDK/
 #JAVA_BIN		?= $(JAVA_HOME)/bin/
-ANDROID_HOME            = /opt/android-sdk
+ANDROID_HOME            ?= /opt/android-sdk
 #ANDROID_TOOLCHAIN       = C:/android_toolchain_$(ANDROID_ARCH)_API$(ANDROID_API_VERSION)
-ANDROID_TOOLCHAIN = /opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/
+ANDROID_TOOLCHAIN ?= /opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/
 
 # find the highest version available of build tools
 ANDROID_BUILD_TOOLS = $(shell ls -1d $(ANDROID_HOME)/build-tools/* | tail -n 1)/
@@ -94,11 +94,10 @@ APP_SCREEN_ORIENTATION ?= landscape
 APP_KEYSTORE_PASS ?= raylib
 
 # Library type used for raylib: STATIC (.a) or SHARED (.so/.dll)
-# attention, ne fonctionne pas avec STATIC (manque la libm quelque part)
-RAYLIB_LIBTYPE ?= SHARED
+RAYLIB_LIBTYPE ?= STATIC
 
 # Library path for libraylib.a/libraylib.so
-RAYLIB_LIB_PATH = $(RAYLIB_PATH)/src/android/
+RAYLIB_LIB_PATH = $(RAYLIB_PATH)/src/
 
 # Shared libs must be added to APK if required
 # NOTE: Generated NativeLoader.java automatically load those libraries
@@ -141,7 +140,7 @@ LDFLAGS += -Wl,--build-id -Wl,--no-undefined -Wl,-z,noexecstack -Wl,-z,relro -Wl
 # Force linking of library module to define symbol
 LDFLAGS += -u ANativeActivity_onCreate
 # Library paths containing required libs
-LDFLAGS += -L. -L$(PROJECT_BUILD_PATH)/obj -L$(PROJECT_BUILD_PATH)/lib/$(ANDROID_ARCH_NAME) -L$(ANDROID_TOOLCHAIN)/sysroot/usr/lib/$(ANDROID_TOOLCHAIN_LIBS)
+LDFLAGS += -L. -L$(PROJECT_BUILD_PATH)/obj -L$(PROJECT_BUILD_PATH)/lib/$(ANDROID_ARCH_NAME)
 
 # Define any libraries to link into executable
 # if you want to link libraries (libname.so or libname.a), use the -lname