vim-patch:8.1.2005: the regexp.c file is too big

Problem:    The regexp.c file is too big.
Solution:   Move the backtracking engine to a separate file. (Yegappan
            Lakshmanan, closes vim/vim#4905)
6d7d7cf750

vim-patch:8.1.2010: new file uses old style comments

Problem:    New file uses old style comments.
Solution:   Change to new style comments. (Yegappan Lakshmanan, closes vim/vim#4910)
9490b9a61c

src/nvim/CMakeLists.txt

@@ -135,6 +135,9 @@ foreach(sfile ${NVIM_SOURCES})
   if(${f} MATCHES "^(regexp_nfa.c)$")
     list(APPEND to_remove ${sfile})
   endif()
+  if(${f} MATCHES "^(regexp_bt.c)$")
+    list(APPEND to_remove ${sfile})
+  endif()
   if(WIN32 AND ${f} MATCHES "^(pty_process_unix.c)$")
     list(APPEND to_remove ${sfile})
   endif()
@@ -261,6 +264,7 @@ endif()
 # NVIM_GENERATED_SOURCES: generated source files
 # These lists must be mutually exclusive.
 foreach(sfile ${NVIM_SOURCES}
+              "${CMAKE_CURRENT_LIST_DIR}/regexp_bt.c"
               "${CMAKE_CURRENT_LIST_DIR}/regexp_nfa.c"
               ${GENERATED_API_DISPATCH}
               "${GENERATED_UI_EVENTS_CALL}"

src/nvim/regexp.h

@@ -19,6 +19,7 @@
 // regexp.c
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "regexp.h.generated.h"
+# include "regexp_bt.h.generated.h"
 #endif
 
 #endif  // NVIM_REGEXP_H