diff --git a/build/detect/config/config_detect.c b/build/detect/config/config_detect.c
index 2b59f78bf..5e29defe1 100644
--- a/build/detect/config/config_detect.c
+++ b/build/detect/config/config_detect.c
@@ -33,12 +33,39 @@
 
 */
 
-#define BLIS_INLINE static
-#define BLIS_EXPORT_BLIS
-#include "bli_system.h"
-#include "bli_type_defs.h"
-#include "bli_arch.h"
-#include "bli_cpuid.h"
+// NOTE: This file will likely only ever get compiled as part of the BLIS
+// configure script, and therefore BLIS_CONFIGURETIME_CPUID is guaranteed to
+// be #defined. However, we preserve the cpp conditional for consistency with
+// the other three files mentioned above.
+#ifdef BLIS_CONFIGURETIME_CPUID
+
+  // NOTE: If you need to make any changes to this cpp branch, it's probably
+  // the case that you also need to modify bli_arch.c, bli_cpuid.c, and
+  // bli_env.c. Don't forget to update these other files as needed!
+
+  // The BLIS_ENABLE_SYSTEM macro must be defined so that the correct cpp
+  // branch in bli_system.h is processed. (This macro is normally defined in
+  // bli_config.h.)
+  #define BLIS_ENABLE_SYSTEM
+
+  // Use C-style static inline functions for any static inline functions that
+  // happen to be defined by the headers below. (This macro is normally defined
+  // in bli_config_macro_defs.h.)
+  #define BLIS_INLINE static
+
+  // Since we're not building a shared library, we can forgo the use of the
+  // BLIS_EXPORT_BLIS annotations by #defining them to be nothing. (This macro
+  // is normally defined in bli_config_macro_defs.h.)
+  #define BLIS_EXPORT_BLIS
+
+  #include "bli_system.h"
+  #include "bli_type_defs.h"
+  #include "bli_arch.h"
+  #include "bli_cpuid.h"
+  //#include "bli_env.h"
+#else
+  #include "blis.h"
+#endif
 
 int main( int argc, char** argv )
 {
diff --git a/frame/base/bli_arch.c b/frame/base/bli_arch.c
index 7fe69919f..e1061985e 100644
--- a/frame/base/bli_arch.c
+++ b/frame/base/bli_arch.c
@@ -34,8 +34,26 @@
 */
 
 #ifdef BLIS_CONFIGURETIME_CPUID
+
+  // NOTE: If you need to make any changes to this cpp branch, it's probably
+  // the case that you also need to modify bli_arch.c, bli_cpuid.c, and
+  // bli_env.c. Don't forget to update these other files as needed!
+
+  // The BLIS_ENABLE_SYSTEM macro must be defined so that the correct cpp
+  // branch in bli_system.h is processed. (This macro is normally defined in
+  // bli_config.h.)
+  #define BLIS_ENABLE_SYSTEM
+
+  // Use C-style static inline functions for any static inline functions that
+  // happen to be defined by the headers below. (This macro is normally defined
+  // in bli_config_macro_defs.h.)
   #define BLIS_INLINE static
+
+  // Since we're not building a shared library, we can forgo the use of the
+  // BLIS_EXPORT_BLIS annotations by #defining them to be nothing. (This macro
+  // is normally defined in bli_config_macro_defs.h.)
   #define BLIS_EXPORT_BLIS
+
   #include "bli_system.h"
   #include "bli_type_defs.h"
   #include "bli_arch.h"
diff --git a/frame/base/bli_cpuid.c b/frame/base/bli_cpuid.c
index bc04f5586..5360d3917 100644
--- a/frame/base/bli_cpuid.c
+++ b/frame/base/bli_cpuid.c
@@ -47,12 +47,31 @@
 #endif
 
 #ifdef BLIS_CONFIGURETIME_CPUID
+
+  // NOTE: If you need to make any changes to this cpp branch, it's probably
+  // the case that you also need to modify bli_arch.c, bli_cpuid.c, and
+  // bli_env.c. Don't forget to update these other files as needed!
+
+  // The BLIS_ENABLE_SYSTEM macro must be defined so that the correct cpp
+  // branch in bli_system.h is processed. (This macro is normally defined in
+  // bli_config.h.)
+  #define BLIS_ENABLE_SYSTEM
+
+  // Use C-style static inline functions for any static inline functions that
+  // happen to be defined by the headers below. (This macro is normally defined
+  // in bli_config_macro_defs.h.)
   #define BLIS_INLINE static
+
+  // Since we're not building a shared library, we can forgo the use of the
+  // BLIS_EXPORT_BLIS annotations by #defining them to be nothing. (This macro
+  // is normally defined in bli_config_macro_defs.h.)
   #define BLIS_EXPORT_BLIS
+
   #include "bli_system.h"
   #include "bli_type_defs.h"
-  #include "bli_cpuid.h"
   #include "bli_arch.h"
+  #include "bli_cpuid.h"
+  //#include "bli_env.h"
 #else
   #include "blis.h"
 #endif
diff --git a/frame/base/bli_env.c b/frame/base/bli_env.c
index 23b8e059e..92aba6970 100644
--- a/frame/base/bli_env.c
+++ b/frame/base/bli_env.c
@@ -34,10 +34,30 @@
 */
 
 #ifdef BLIS_CONFIGURETIME_CPUID
+
+  // NOTE: If you need to make any changes to this cpp branch, it's probably
+  // the case that you also need to modify bli_arch.c, bli_cpuid.c, and
+  // bli_env.c. Don't forget to update these other files as needed!
+
+  // The BLIS_ENABLE_SYSTEM macro must be defined so that the correct cpp
+  // branch in bli_system.h is processed. (This macro is normally defined in
+  // bli_config.h.)
+  #define BLIS_ENABLE_SYSTEM
+
+  // Use C-style static inline functions for any static inline functions that
+  // happen to be defined by the headers below. (This macro is normally defined
+  // in bli_config_macro_defs.h.)
   #define BLIS_INLINE static
+
+  // Since we're not building a shared library, we can forgo the use of the
+  // BLIS_EXPORT_BLIS annotations by #defining them to be nothing. (This macro
+  // is normally defined in bli_config_macro_defs.h.)
   #define BLIS_EXPORT_BLIS
+
   #include "bli_system.h"
   #include "bli_type_defs.h"
+  //#include "bli_arch.h"
+  //#include "bli_cpuid.h"
   #include "bli_env.h"
 #else
   #include "blis.h"
diff --git a/frame/include/bli_system.h b/frame/include/bli_system.h
index 2541018ac..79333017b 100644
--- a/frame/include/bli_system.h
+++ b/frame/include/bli_system.h
@@ -70,7 +70,7 @@
 #endif
 
 // Determine the target operating system.
-//#if defined(BLIS_ENABLE_SYSTEM)
+#if defined(BLIS_ENABLE_SYSTEM)
   #if defined(_WIN32) || defined(__CYGWIN__)
     #define BLIS_OS_WINDOWS 1
   #elif defined(__gnu_hurd__)
@@ -94,9 +94,9 @@
   #else
     #error "Cannot determine operating system"
   #endif
-//#else // #if defined(BLIS_DISABLE_SYSTEM)
-//  #define BLIS_OS_NONE
-//#endif
+#else // #if defined(BLIS_DISABLE_SYSTEM)
+  #define BLIS_OS_NONE
+#endif
 
 // A few changes that may be necessary in Windows environments.
 #if BLIS_OS_WINDOWS
diff --git a/frame/include/blis.h b/frame/include/blis.h
index a42c7cce8..b374e8539 100644
--- a/frame/include/blis.h
+++ b/frame/include/blis.h
@@ -48,6 +48,15 @@ extern "C" {
 // NOTE: PLEASE DON'T CHANGE THE ORDER IN WHICH HEADERS ARE INCLUDED UNLESS
 // YOU ARE SURE THAT IT DOESN'T BREAK INTER-HEADER MACRO DEPENDENCIES.
 
+// -- configure definitions --
+
+// NOTE: bli_config.h header must be included before any BLIS header.
+// It is bootstrapped by ./configure and does not depend on later
+// headers. Moreover, these configuration variables are necessary to change
+// some default behaviors (e.g. disable OS-detection in bli_system.h in case
+// of --disable-system).
+#include "bli_config.h"
+
 // -- System and language-related headers --
 
 // NOTE: bli_system.h header must be included before bli_config_macro_defs.h.
@@ -55,9 +64,8 @@ extern "C" {
 #include "bli_lang_defs.h"
 
 
-// -- configure definitions --
+// -- configure default definitions --
 
-#include "bli_config.h"
 #include "bli_config_macro_defs.h"