Remove redundant -DCMAKE_BUILD_TYPE=Release flags

Since commit 183d05a0 in 2012, this is the default.

fixes #18000

pkgs/development/compilers/llvm/3.5/clang.nix

@@ -15,7 +15,6 @@ in stdenv.mkDerivation {
   buildInputs = [ cmake libedit libxml2 llvm ];
 
   cmakeFlags = [
-    "-DCMAKE_BUILD_TYPE=Release"
     "-DCMAKE_CXX_FLAGS=-std=c++11"
   ] ++
   # Maybe with compiler-rt this won't be needed?

pkgs/development/compilers/llvm/3.5/libc++/default.nix

@@ -24,13 +24,12 @@ stdenv.mkDerivation rec {
 
   buildInputs = [ cmake libcxxabi ] ++ lib.optional stdenv.isDarwin fixDarwinDylibNames;
 
-  cmakeFlags =
-    [ "-DCMAKE_BUILD_TYPE=Release"
-      "-DLIBCXX_LIBCXXABI_INCLUDE_PATHS=${libcxxabi}/include"
-      "-DLIBCXX_LIBCXXABI_LIB_PATH=${libcxxabi}/lib"
-      "-DLIBCXX_LIBCPPABI_VERSION=2"
-      "-DLIBCXX_CXX_ABI=libcxxabi"
-    ];
+  cmakeFlags = [
+    "-DLIBCXX_LIBCXXABI_INCLUDE_PATHS=${libcxxabi}/include"
+    "-DLIBCXX_LIBCXXABI_LIB_PATH=${libcxxabi}/lib"
+    "-DLIBCXX_LIBCPPABI_VERSION=2"
+    "-DLIBCXX_CXX_ABI=libcxxabi"
+  ];
 
   enableParallelBuilding = true;
 

pkgs/development/compilers/llvm/3.5/lld.nix

@@ -14,7 +14,6 @@ stdenv.mkDerivation {
   buildInputs = [ cmake ncurses zlib python ];
 
   cmakeFlags = [
-    "-DCMAKE_BUILD_TYPE=Release"
     "-DCMAKE_CXX_FLAGS=-std=c++11"
     "-DLLD_PATH_TO_LLVM_BUILD=${llvm}"
   ];

pkgs/development/compilers/llvm/3.5/lldb.nix

@@ -26,7 +26,6 @@ stdenv.mkDerivation {
   buildInputs = [ cmake python which swig ncurses zlib libedit ];
 
   cmakeFlags = [
-    "-DCMAKE_BUILD_TYPE=Release"
     "-DCMAKE_CXX_FLAGS=-std=c++11"
     "-DLLDB_PATH_TO_LLVM_BUILD=${llvm}"
     "-DLLDB_PATH_TO_CLANG_BUILD=${clang}"

pkgs/development/compilers/llvm/3.5/polly.nix

@@ -10,7 +10,6 @@ stdenv.mkDerivation {
   buildInputs = [ cmake isl python gmp ];
 
   cmakeFlags = [
-    "-DCMAKE_BUILD_TYPE=Release"
     "-DCMAKE_CXX_FLAGS=-std=c++11"
     "-DLLVM_INSTALL_ROOT=${llvm}"
   ];