File fix-makefile-installation.patch of Package pamixer

diff -Nur pamixer-1.5/Makefile new/Makefile
--- pamixer-1.5/Makefile	2021-10-04 10:09:29.000000000 +0200
+++ new/Makefile	2021-11-06 12:32:09.179999619 +0100
@@ -1,6 +1,8 @@
 LDLIBS   ?= -lpulse -lboost_program_options
-CXXFLAGS ?= -std=c++11 -Wall -Werror -Wextra -pedantic -DVERSION=\"1.5\"
+CXXFLAGS ?= -Wall -Werror -Wextra -pedantic
+CXXFLAGS += -std=c++11 -DVERSION=\"1.5\"
 PREFIX   ?= /usr/local
+MANDIR   ?= $(PREFIX)/man
 RM       ?= rm -f
 
 target   := pamixer
@@ -28,6 +30,6 @@
 install: pamixer
 	install -d $(DESTDIR)$(PREFIX)/bin/
 	install $(target) $(DESTDIR)$(PREFIX)/bin/
-	install -d $(DESTDIR)$(PREFIX)/man/man1/
-	install $(manpage) $(DESTDIR)$(PREFIX)/man/man1/
-	gzip $(DESTDIR)$(PREFIX)/man/man1/$(manpage)
+	install -d $(DESTDIR)$(MANDIR)/man1/
+	install -m 644 $(manpage) $(DESTDIR)$(MANDIR)/man1/
+	gzip $(DESTDIR)$(MANDIR)/man1/$(manpage)