Revert "Allow customized relative PYTHONHOME"

This reverts commit 0bb90628b5f7c170689d2d3f019af773772fc649 since it is causing failures on the Windows LLDB buildbot:

http://lab.llvm.org:8011/builders/lldb-x64-windows-ninja/builds/14048
diff --git a/lldb/cmake/modules/LLDBConfig.cmake b/lldb/cmake/modules/LLDBConfig.cmake
index 6b10f73..fb4512a 100644
--- a/lldb/cmake/modules/LLDBConfig.cmake
+++ b/lldb/cmake/modules/LLDBConfig.cmake
@@ -59,6 +59,7 @@
 add_optional_dependency(LLDB_ENABLE_PYTHON "Enable Python scripting support in LLDB" PythonInterpAndLibs PYTHONINTERPANDLIBS_FOUND)
 add_optional_dependency(LLDB_ENABLE_LIBXML2 "Enable Libxml 2 support in LLDB" LibXml2 LIBXML2_FOUND VERSION 2.8)
 
+option(LLDB_RELOCATABLE_PYTHON "Use the PYTHONHOME environment variable to locate Python." OFF)
 option(LLDB_USE_SYSTEM_SIX "Use six.py shipped with system and do not install a copy of it" OFF)
 option(LLDB_USE_ENTITLEMENTS "When codesigning, use entitlements if available" ON)
 option(LLDB_BUILD_FRAMEWORK "Build LLDB.framework (Darwin only)" OFF)
@@ -139,20 +140,10 @@
 endif()
 
 if (LLDB_ENABLE_PYTHON)
-  if(CMAKE_SYSTEM_NAME MATCHES "Windows")
-    set(default_embed_python_home ON)
-  else()
-    set(default_embed_python_home OFF)
-  endif()
-  option(LLDB_EMBED_PYTHON_HOME
-    "Embed PYTHONHOME in the binary. If set to OFF, PYTHONHOME environment variable will be used to to locate Python."
-    ${default_embed_python_home})
-
   include_directories(${PYTHON_INCLUDE_DIRS})
-  if (LLDB_EMBED_PYTHON_HOME)
+  if ("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows" AND NOT LLDB_RELOCATABLE_PYTHON)
     get_filename_component(PYTHON_HOME "${PYTHON_EXECUTABLE}" DIRECTORY)
-    set(LLDB_PYTHON_HOME "${PYTHON_HOME}" CACHE STRING
-      "Path to use as PYTHONHOME in lldb. If a relative path is specified, it will be resolved at runtime relative to liblldb directory.")
+    file(TO_CMAKE_PATH "${PYTHON_HOME}" LLDB_PYTHON_HOME)
   endif()
 endif()
 
diff --git a/lldb/include/lldb/Host/Config.h.cmake b/lldb/include/lldb/Host/Config.h.cmake
index 42f4ca1a..e9065ed 100644
--- a/lldb/include/lldb/Host/Config.h.cmake
+++ b/lldb/include/lldb/Host/Config.h.cmake
@@ -46,8 +46,6 @@
 
 #cmakedefine01 LLDB_ENABLE_PYTHON
 
-#cmakedefine01 LLDB_EMBED_PYTHON_HOME
-
 #cmakedefine LLDB_PYTHON_HOME "${LLDB_PYTHON_HOME}"
 
 #define LLDB_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}"
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index f046bcf..722af71 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -277,36 +277,14 @@
 
 private:
   void InitializePythonHome() {
-#if LLDB_EMBED_PYTHON_HOME
+#if defined(LLDB_PYTHON_HOME)
 #if PY_MAJOR_VERSION >= 3
-    typedef const wchar_t* str_type;
+    size_t size = 0;
+    static wchar_t *g_python_home = Py_DecodeLocale(LLDB_PYTHON_HOME, &size);
 #else
-    typedef char* str_type;
+    static char g_python_home[] = LLDB_PYTHON_HOME;
 #endif
-    static str_type g_python_home = []() -> str_type {
-      const char *lldb_python_home = LLDB_PYTHON_HOME;
-      const char *absolute_python_home = nullptr;
-      llvm::SmallString<64> path;
-      if (llvm::sys::path::is_absolute(lldb_python_home)) {
-        absolute_python_home = lldb_python_home;
-      } else {
-        FileSpec spec = HostInfo::GetShlibDir();
-        if (!spec)
-          return nullptr;
-        spec.GetPath(path);
-        llvm::sys::path::append(path, lldb_python_home);
-        absolute_python_home = path.c_str();
-      }
-#if PY_MAJOR_VERSION >= 3
-      size_t size = 0;
-      return Py_DecodeLocale(absolute_python_home, &size);
-#else
-      return strdup(absolute_python_home);
-#endif
-    }();
-    if (g_python_home != nullptr) {
-      Py_SetPythonHome(g_python_home);
-    }
+    Py_SetPythonHome(g_python_home);
 #else
 #if defined(__APPLE__) && PY_MAJOR_VERSION == 2 && PY_MINOR_VERSION == 7
     // For Darwin, the only Python version supported is the one shipped in the