https://github.com/Rakashazi/emu-ex-plus-alpha

• Java

    sudo add-apt-repository ppa:webupd8team/java
    sudo apt-get update
    sudo apt-get install oracle-java8-installer
  

• Others

    sudo apt-get install libc6:i386 libncurses5:i386 libstdc++6:i386 lib32z1 libbz2-1.0:i386
  

  Maybe

    sudo apt-get install liblzma
  

• Compilers

    sudo apt-get install cmake gcc g++
    sudo apt-get install build-essential
    sudo apt-get install ant pkg-config autoconf autogen
    sudo apt-get install build-essential libtool
    sudo apt-get install texinfo lldb
  

  Maybe

    sudo apt-get install clang
    sudo apt-get install xzdec
  

1. Download and unpack NDK from https://developer.android.com/ndk/downloads/index.html
   Put it in the home folder and rename it as android-ndk

2. Download and unpack the project from https://github.com/Rakashazi/emu-ex-plus-alpha/archive/master.zip
   Put it in the home folder

3. Download and install android studio from https://developer.android.com/studio/index.html
   Put it in the /opt folder and launch /android-studio/bin/studio.sh
   

4. Download By SDK Manager:
   

   • SDK Platforms:
     • Android 7.1.1 SDK 25 (Optional)
     • Android 7.0.0 SDK 24* (Important)
     • Android 4.0.3 SDK 15 (Optional)
     • Android 2.3.3 SDK 10* (Important)
     • Android 2.3 SDK 9 (Optional)
   • SDK Tools:
     • CMake (Optional)
     • LLDB (Optional)
     • NDK (Optional)
     • Android Support Repository (Important)

1. Get PKG_CONFIG_PATH by:

   pkg-config --variable pc_path pkg-config
   

2. Get IMAGINE_PATH by:

   cd ~/emu-ex-plus-alpha-master/
   pwd
   

3. Get ANDROID_HOME where there is sdk, ~/Android/Sdk

4. Put them in the ~/.profile like below

5. Logout and login to make effective the changes because source ~/.profile affect current shell only

   ~/.profile could be change, so check the current file if you are in different environment
   

   Example my ~/.profile

   # set PATH so it includes user's private bin directories
   PATH="$HOME/bin:$HOME/.local/bin:$PATH:$IMAGINE_PATH:$PKG_CONFIG_PATH:ANDROID_HOME"
   export IMAGINE_PATH="$HOME/emu-ex-plus-alpha-master/imagine"
   export PKG_CONFIG_PATH="/usr/local/lib/x86_64-linux-gnu/pkgconfig:/usr/local/lib/pkgconfig:/usr/local/share/pkgconfig:/usr/lib/x86_64-linux-gnu/pkgconfig:/usr/lib/pkgconfig:/usr/share/pkgconfig"
   export ANDROID_HOME="$HOME/Android/Sdk"
   

6. To avoid bugs be sure that there are FILE pointer:

   cd ~/emu-ex-plus-alpha-master/imagine
   ls --file-type | grep "@"
   

   The output should be like:

   android.mk@
   android-release.mk@
   ios.mk@
   ios-release.mk@
   linux-armv7-pandora.mk@
   linux-armv7-pandora-release.mk@
   linux-x86_64.mk@
   linux-x86_64-release.mk@
   linux-x86.mk@
   linux-x86-release.mk@
   macosx-x86_64.mk@
   ouya.mk@
   ouya-release.mk@
   

   If it's empty try to continue or, if there are errors, download
   and unzip again the copy get from github.

1. First, something you should know:

   1. make options:

      • V=1 it's verbose
      • -j4 it's -j< n-core >

   2. Ignore dirname's errors, it's a bug of /emu-ex-plus-alpha-master/imagine/make/setAndroidNDKPath.mk when it try to use which to find NDK path, but it's ok.

      ANDROID_NDK_PATH ?= $(shell dirname `which ndk-build`)
      

   3. My personal fix, edit /emu-ex-plus-alpha-master/imagine/make/shortcut/meta-builds/android.mk
      I've tried to edit this variable

      android_sdkToolsPath := $(shell dirname `which android`)
      

      as

      android_sdkToolsPath := $(HOME)/Android
      

   4. To retray the compilation:

      rm /tmp/imagine-bundle
      rm ~/imagine-sdk
      rm ~/emu-ex-plus-alpha-master
      

2. Open the Terminal (I've tried Android only)

   cd ~/emu-ex-plus-alpha-master/imagine/bundle/all/
   bash makeAll-android.sh V=1 -j4
   

   Check if there are errors:

   bash makeAll-android.sh V=1 -j4 1>/dev/null | grep -v "dirname"
   

3. It's necessary

   cd ~/emu-ex-plus-alpha-master/imagine/	
   make -f android-java.mk install
   

   If there are errors, check /Android/Sdk/extras/android/m2repository/com/android/support/ and be sure there is support-v4 folder
   If there is not install Android Support Repository in the SDK Manager
   In this file there is a problem, I've tried my personal fix editing in /emu-ex-plus-alpha-master/imagine/android-java.mk these commands, but it's doesn't work when I try to compile GBC.emu
   

   install : main
   install-links : main
   

   as

   install : all
   install-links : all
   

4. Now, it's time to build android version

   1. Debug version:

      1. Compile image

         cd ~/emu-ex-plus-alpha-master/imagine/
         make -f android.mk V=1 -j4
         make -f android.mk install V=1 -j4
         

         Check if there are errors:

         make -f android.mk install V=1 -j4 1>/dev/null | grep -v "dirname"
         

      2. Compile EmuFramework

          cd ~/emu-ex-plus-alpha-master/EmuFramework
          make -f android.mk V=1 -j4
          make -f android.mk install V=1 -j4
         

         Check if there are errors:

          make -f android.mk install V=1 -j4 1>/dev/null | grep -v "dirname"
         

   2. Release version:

      1. Compile image

          cd ~/emu-ex-plus-alpha-master/imagine/
          make -f android-release.mk V=1 -j4
          make -f android-release.mk install V=1 -j4
         

         Check if there are errors:

          make -f android-release.mk install V=1 -j4 1>/dev/null | grep -v "dirname"	
         

      2. Compile EmuFramework

         cd ~/emu-ex-plus-alpha-master/EmuFramework
         make -f android-release.mk V=1 -j4
         make -f android-release.mk install V=1 -j4
         

         Check if there are errors:

         make -f android-release.mk install V=1 -j4 1>/dev/null | grep -v "dirname"
         

5. To build android release version (I've tried GBC.emu):

   cd ~/emu-ex-plus-alpha-master/GBC.emu
   make -f android-9.mk V=1 -j4 
   make -f android-9.mk install V=1 -j4
   

https://www.reddit.com/r/AndroidGaming/comments/32zasy/what_do_you_think_of_robert_broglias_emu_series/cqjslx0/

Well this thread lit a bit of a fire under my ass. If I am not willing to put a bit of effort into obtaining these emulators the legal way (compiling from source, as per GPL) then I probably don't deserve to stomp on someone else's efforts and rights to profit either. Obviously Robert has put a lot of work into his front end and making it cross platform and he reserves some right to seek compensation from users for that work.
So... I did exactly that. Downloaded the source code to a linux box and painstakingly figured out how to compile it.
Seriously. This took me > 10 hours to get everything worked out so hope you have a comfy chair.
I am not going to do an exact step by step for people but basically:

You need a linux box 
Get your GCC version up to 4.9 or higher 
Get your GNU Make version up to 3.8.2 or higher 
Install Android SDK 
Install Android NDK 
Install JDK 
Install Ant 
Install all the other compiling essentials 

Download the source. Compiling the source follows this order of operation:

Read documentation in Imagine/docs folder 
Compile + Install Imagine pre-requisites from /imagine/bundle/all/ 
Compile + Install Imagine 
Compile + Install EmuFramework 
Compile the emulator you want to use 
Sign the APK 

I'm hugely over simplifying things. Good luck to all who set out to accomplish this starting from little or no knowledge of compiling c++ based android apps.