libmikey: better nix integration

this sets up libmikey on LIBRARY_PATH and C_INCLUDE_PATH, and uses
these environment variables for e.g. -lmikey instead of figuring out
the hard-coded paths.

(still learning all these c standards: naming the archive `libX`,
linking with `-lX`, includes go in `include/X/*.h` etc. -- I think!)

this means that in my standard bash environment I can just compile
code with -lmikey and #include <libmikey/common.h> etc and it will
work, in addition to compiling nicely within the nix builder.

bash/nix

@@ -13,6 +13,10 @@ if [ -e $HOME/.nix-profile/include ]; then
     export C_INCLUDE_PATH=$HOME/.nix-profile/include:$C_INCLUDE_PATH;
 fi
 
+if [ -e $HOME/.nix-profile/lib ]; then
+    export LIBRARY_PATH=$HOME/.nix-profile/lib:$LIBRARY_PATH;
+fi
+
 # i'm not sure but i dont think i should do this:
 # if [ -e $HOME/.nix-profile/lib ]; then
 #     export LD_LIBRARY_PATH=$HOME/.nix-profile/lib:$LD_LIBRARY_PATH;

nix/nixpkgs/config.nix

@@ -38,10 +38,10 @@
     hello_world = stdenv.mkDerivation {
       name = "hello_world";
       src = ~/.dotfiles/src/hello_world;
-      libmikey = libmikey;
+      buildInputs = [ libmikey ];
       installPhase = ''
-      mkdir -p $out/bin
-      cp hello_world $out/bin/hello_world
+        mkdir -p $out/bin
+        cp hello_world $out/bin/hello_world
       '';
     };
 
@@ -187,6 +187,7 @@
     devEnv = buildEnv {
       name = "devEnv";
       paths = [
+        libmikey
         myHaskellEnv
         cabal2nix
 

nix/pkgs/libmikey/default.nix

@@ -4,8 +4,8 @@ stdenv.mkDerivation {
   src = ~/.dotfiles/src/libmikey;
   installPhase = ''
     mkdir -p $out/lib
-    mkdir -p $out/include
-    cp build/include/* $out/include
+    mkdir -p $out/include/mikey
+    cp build/include/* $out/include/mikey
     cp build/lib/* $out/lib
   '';
 }

src/hello_world/.gitignore

@@ -0,0 +1,2 @@
+*.o
+hello_world

src/hello_world/Makefile

@@ -1,11 +1,10 @@
 .PHONY: clean
 
-LIBS = -static -lmikey
-CFLAGS = ${include_dirs} -O
-include_dirs = -I${libmikey}/include
+LIBS = -lmikey
+CFLAGS = -O
 
 hello_world: hello_world.o
-	$(CC) -o $@ $^ $(CFLAGS) $(libmikey)/lib/libmikey.a
+	$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
 
 clean:
 	rm -f *.o

src/hello_world/hello_world.c

@@ -1,6 +1,6 @@
 #include <stdio.h>
-#include "common.h"
-#include "error_functions.h"
+#include <mikey/common.h>
+#include <mikey/error_functions.h>
 
 /**
  * Example program.

src/libmikey/.gitignore

@@ -0,0 +1,4 @@
+build/
+ename.c.inc
+*.o
+*.a