diff --git a/CMakeLists.txt b/CMakeLists.txt
index bd75929..07652e9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -134,11 +134,11 @@ CHECK_INCLUDE_FILE(sys/types.h  HAVE_SYS_TYPES_H)
 CHECK_INCLUDE_FILE(unistd.h     HAVE_UNISTD_H)
 CHECK_INCLUDE_FILE(windows.h    HAVE_WINDOWS_H)
 
-CHECK_FUNCTION_EXISTS(bcopy         HAVE_BCOPY)
-CHECK_FUNCTION_EXISTS(memfd_create  HAVE_MEMFD_CREATE)
-CHECK_FUNCTION_EXISTS(memmove       HAVE_MEMMOVE)
-CHECK_FUNCTION_EXISTS(secure_getenv HAVE_SECURE_GETENV)
-CHECK_FUNCTION_EXISTS(strerror      HAVE_STRERROR)
+CHECK_SYMBOL_EXISTS(bcopy         "strings.h"  HAVE_BCOPY)
+CHECK_SYMBOL_EXISTS(memfd_create  "sys/mman.h" HAVE_MEMFD_CREATE)
+CHECK_SYMBOL_EXISTS(memmove       "string.h"   HAVE_MEMMOVE)
+CHECK_SYMBOL_EXISTS(secure_getenv "stdlib.h"   HAVE_SECURE_GETENV)
+CHECK_SYMBOL_EXISTS(strerror      "string.h"   HAVE_STRERROR)
 
 set(ORIG_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
 set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror")
diff --git a/ChangeLog b/ChangeLog
index 1871d3d..0ce683f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -31,6 +31,12 @@ invalid utf8 mode is enabled.
     allow spaces in directory names.
 
   - This fixes a cmake error, if the path of the pcre2 source contains a space.
+  
+5. Updated CMakeLists.txt with a patch from B. Scott Michel: CMake's 
+documentation suggests using CHECK_SYMBOL_EXISTS over CHECK_FUNCTION_EXIST. 
+Moreover, these functions come from specific header files, which need to be 
+specified (and, thankfully, are the same on both the Linux and WinXX 
+platforms.)  
 
 
 Version 10.35 09-May-2020