DOC: fix libreadline dependency

Author: q4a

doc/howto/build-linux.txt

@@ -16,7 +16,7 @@ JPEG
 
 
 Ubuntu 18.04 build dependencies:
-sudo apt install git cmake libfreeimage-dev liblockfile-dev libopenal-dev libtbb-dev libcrypto++-dev libpugixml-dev libogg-dev libtheora-dev libvorbis-dev libsdl2-dev liblzo2-dev libjpeg-dev libncurses5-dev
+sudo apt install git cmake libfreeimage-dev liblockfile-dev libopenal-dev libtbb-dev libcrypto++-dev libpugixml-dev libogg-dev libtheora-dev libvorbis-dev libsdl2-dev liblzo2-dev libjpeg-dev libncurses5-dev libreadline-dev
 
 Build commands:
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