mass rewrite of find parameters to cross-platform style

Fixes #9044, close #9667. Thanks to @taku0 for suggesting this solution.
Now we have no modes starting with `/` or `+`.

Rewrite the `-perm` parameters of find:
 - completely safe: rewrite `/0100` and `+100` to `-0100`,
 - slightly semantics-changing: rewrite `+111` to `-0100`.
I cross-verified the `find` manual pages for Linux, Darwin, FreeBSD.

pkgs/development/compilers/ghc/6.10.2-binary.nix

@@ -38,7 +38,7 @@ stdenv.mkDerivation rec {
     # On Linux, use patchelf to modify the executables so that they can
     # find editline/gmp.
     (if stdenv.isLinux then ''
-      find . -type f -perm +100 \
+      find . -type f -perm -0100 \
           -exec patchelf --interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" \
           --set-rpath "${libedit}/lib:${ncurses}/lib:${gmp}/lib" {} \;
       for prog in ld ar gcc strip ranlib; do

pkgs/development/compilers/ghc/7.0.4-binary.nix

@@ -60,7 +60,7 @@ stdenv.mkDerivation rec {
     # On Linux, use patchelf to modify the executables so that they can
     # find editline/gmp.
     stdenv.lib.optionalString stdenv.isLinux ''
-      find . -type f -perm +100 \
+      find . -type f -perm -0100 \
           -exec patchelf --interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" \
           --set-rpath "${ncurses}/lib:${gmp}/lib" {} \;
       sed -i "s|/usr/bin/perl|perl\x00        |" ghc-${version}/ghc/stage2/build/tmp/ghc-stage2

pkgs/development/compilers/ghc/7.4.2-binary.nix

@@ -62,7 +62,7 @@ stdenv.mkDerivation rec {
     stdenv.lib.optionalString stdenv.isLinux ''
       mkdir -p "$out/lib"
       ln -sv "${ncurses}/lib/libncurses.so" "$out/lib/libncurses${stdenv.lib.optionalString stdenv.is64bit "w"}.so.5"
-      find . -type f -perm +100 \
+      find . -type f -perm -0100 \
           -exec patchelf --interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" \
           --set-rpath "$out/lib:${gmp}/lib" {} \;
       sed -i "s|/usr/bin/perl|perl\x00        |" ghc-${version}/ghc/stage2/build/tmp/ghc-stage2