diff --git a/configure.ac b/configure.ac
index ec9e03a23b..4a8326b5e2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -85,6 +85,14 @@ if test x"$enable_cocoa" = xyes ; then
   AC_DEFINE(VERSION_STRING, "3.0.0", [Version string to use for var directory])
 fi
 
+dnl Set minimum targeted version of macOS.
+AC_ARG_VAR([MACOS_MIN], [minimum version number of macOS to target; default is 10.15 which is the oldest version that the source code can handle])
+if test x"$MACOS_MIN" = x ; then
+    AC_SUBST(MACOS_MIN_INTERNAL, 10.15)
+else
+    AC_SUBST(MACOS_MIN_INTERNAL, $MACOS_MIN)
+fi
+
 dnl Checks for libraries.
 dnl Replace `main' with a function in -lncurses:
 if test x"$enable_cocoa" != xyes ; then
diff --git a/src/Makefile.am b/src/Makefile.am
index b4e5972518..e0b80af0cb 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1143,11 +1143,11 @@ hengband_SOURCES += \
 	cocoa/AngbandAudio.mm \
 	cocoa/SoundAndMusic.h \
 	cocoa/SoundAndMusic.mm
-AM_CFLAGS = -mmacosx-version-min=10.15 -Wunguarded-availability
-AM_OBJCXXFLAGS = -std=c++20 -fobjc-arc -mmacosx-version-min=10.15 -Wunguarded-availability -stdlib=libc++
-AM_CXXFLAGS = -mmacosx-version-min=10.15 -Wunguarded-availability -stdlib=libc++
+AM_CFLAGS = -mmacosx-version-min=${MACOS_MIN_INTERNAL} -Wunguarded-availability
+AM_OBJCXXFLAGS = -std=c++20 -fobjc-arc -mmacosx-version-min=${MACOS_MIN_INTERNAL} -Wunguarded-availability -stdlib=libc++
+AM_CXXFLAGS = -mmacosx-version-min=${MACOS_MIN_INTERNAL} -Wunguarded-availability -stdlib=libc++
 hengband_LDFLAGS = -framework cocoa -framework AVFoundation $(AM_LDFLAGS)
-hengband_LINK = MACOSX_DEPLOYMENT_TARGET=10.15 $(OBJCXXLINK) $(hengband_LDFLAGS) $(LDFLAGS) -o $@
+hengband_LINK = MACOSX_DEPLOYMENT_TARGET=${MACOS_MIN_INTERNAL} $(OBJCXXLINK) $(hengband_LDFLAGS) $(LDFLAGS) -o $@
 APPNAME = $(PACKAGE_NAME)
 APPEXE = hengband
 APPDIR = $(APPNAME).app
diff --git a/src/main-cocoa.mm b/src/main-cocoa.mm
index 8eac70592d..15fc8376d8 100644
--- a/src/main-cocoa.mm
+++ b/src/main-cocoa.mm
@@ -1917,8 +1917,8 @@ static BOOL graphics_will_be_enabled(void)
 
 #pragma mark Prototypes
 static void wakeup_event_loop(void);
-static void hook_plog(const char *str);
-static void hook_quit(const char * str);
+static void hook_plog(std::string_view str);
+static void hook_quit(std::string_view str);
 static NSString* get_lib_directory(void);
 static NSString* get_doc_directory(void);
 static NSString* AngbandCorrectedDirectoryPath(NSString *originalPath);
@@ -5182,14 +5182,15 @@ static BOOL check_events(int wait)
 /**
  * Hook to tell the user something important
  */
-static void hook_plog(const char * str)
+static void hook_plog(std::string_view str)
 {
-    if (str)
+    if (str.size() > 0)
     {
 	NSString *msg = NSLocalizedStringWithDefaultValue(
 	    @"Warning", AngbandMessageCatalog, [NSBundle mainBundle],
 	    @"Warning", @"Alert text for generic warning");
-        NSString *info = [NSString stringWithCString:str
+        NSString *info = [[NSString alloc] initWithBytes:str.data()
+				   length:str.size()
 #ifdef JP
 				   encoding:NSJapaneseEUCStringEncoding
 #else
@@ -5208,7 +5209,7 @@ static void hook_plog(const char * str)
 /**
  * Hook to tell the user something, and then quit
  */
-static void hook_quit(const char * str)
+static void hook_quit(std::string_view str)
 {
     for (int i = ANGBAND_TERM_MAX - 1; i >= 0; --i) {
         if (angband_terms[i]) {
diff --git a/src/util/angband-files.cpp b/src/util/angband-files.cpp
index 5645319e78..9e9ee2c9e6 100644
--- a/src/util/angband-files.cpp
+++ b/src/util/angband-files.cpp
@@ -284,6 +284,9 @@ static std::optional<std::string> read_line(FILE *fp)
         int c = fgetc(fp);
 
         if (c == EOF) {
+            buf[i] = '\0';
+            std::string_view sv(buf);
+            line_buf.append(sv.begin(), sv.end());
             break;
         }
         /*