[cmake] Minor improvements in top-level CMakeLists.txt

CMakeLists.txt

@@ -44,7 +44,7 @@ if(NOT ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR} VERSION_EQUAL ${TRIQS_V
   message(FATAL_ERROR "The ${PROJECT_NAME} version ${PROJECT_VERSION} is not compatible with TRIQS version ${TRIQS_VERSION}.")
 endif()
 
-# Default Install directory to TRIQS_ROOT if not given or invalid.
+# Default Install directory to TRIQS_ROOT if not given or when provided as relative path.
 if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT OR (NOT IS_ABSOLUTE ${CMAKE_INSTALL_PREFIX}))
   message(STATUS "No install prefix given (or invalid). Defaulting to TRIQS_ROOT")
   set(CMAKE_INSTALL_PREFIX ${TRIQS_ROOT} CACHE PATH "default install path" FORCE)
@@ -87,12 +87,12 @@ if(Build_Tests)
   enable_testing()
 endif()
 
-# Build static libraries by default
-option(BUILD_SHARED_LIBS "Enable compilation of shared libraries" OFF)
-
 # ############
 # Global Compilation Settings
 
+# Build static libraries by default
+option(BUILD_SHARED_LIBS "Enable compilation of shared libraries" OFF)
+
 # Export the list of compile-commands into compile_commands.json
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)