Cleanup: remove redundant define checks

Also reformat checks to quiet warnings so they don't read as empty
define checks.

intern/eigen/intern/matrix.cc

@@ -14,7 +14,8 @@
 #  pragma GCC diagnostic ignored "-Wlogical-op"
 #endif
 
-#ifdef __EIGEN3_MATRIX_C_API_CC__ /* quiet warning */
+#ifdef __EIGEN3_MATRIX_C_API_CC__
+/* Quiet warning. */
 #endif
 
 #include <Eigen/Core>

intern/eigen/intern/svd.cc

@@ -14,7 +14,8 @@
 #  pragma GCC diagnostic ignored "-Wlogical-op"
 #endif
 
-#ifdef __EIGEN3_SVD_C_API_CC__ /* quiet warning */
+#ifdef __EIGEN3_SVD_C_API_CC__
+/* Quiet warning. */
 #endif
 
 #include <Eigen/Core>

source/blender/blenkernel/intern/blender.cc

@@ -323,7 +323,8 @@ static void userdef_free_addons(UserDef *userdef)
 void BKE_blender_userdef_data_free(UserDef *userdef, bool clear_fonts)
 {
 #define U BLI_STATIC_ASSERT(false, "Global 'U' not allowed, only use arguments passed in!")
-#ifdef U /* quiet warning */
+#ifdef U
+  /* Quiet warning. */
 #endif
 
   userdef_free_keymaps(userdef);

source/blender/blenlib/intern/array_store.c

@@ -1159,7 +1159,8 @@ static BChunkList *bchunk_list_from_data_merge(const BArrayInfo *info,
   /* Warning, from now on don't use len(data) since we want to ignore chunks already matched. */
   size_t data_len = data_len_original;
 #define data_len_original invalid_usage
-#ifdef data_len_original /* Quiet warning. */
+#ifdef data_len_original
+  /* Quiet warning. */
 #endif
 
   const BChunkRef *chunk_list_reference_last = NULL;

source/blender/bmesh/tools/bmesh_intersect.cc

@@ -30,8 +30,6 @@
 
 #include "BLI_linklist_stack.h"
 #include "BLI_utildefines_stack.h"
-#ifndef NDEBUG
-#endif
 
 #include "BLI_buffer.h"
 #include "BLI_kdopbvh.h"

source/blender/editors/space_script/space_script.cc

@@ -28,9 +28,6 @@
 
 #include "BLO_read_write.hh"
 
-#ifdef WITH_PYTHON
-#endif
-
 #include "script_intern.h" /* own include */
 
 // static script_run_python(char *funcname, )