Makefile: move -DPAGER_ENV from BASIC_CFLAGS to EXTRA_CPPFLAGS

Remove -DPAGER_ENV from the BASIC_CFLAGS and instead have it passed
via the EXTRA_CPPFLAGS passed when compiling pager.c.

This doesn't change anything except to make it clear that only pager.c
needs this, as it's the only user of this define. See
995bc22d7f (pager: move pager-specific setup into the build,
2016-08-04) for the commit that originally added this.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -2104,11 +2104,6 @@ ifdef DEFAULT_HELP_FORMAT
 BASIC_CFLAGS += -DDEFAULT_HELP_FORMAT='"$(DEFAULT_HELP_FORMAT)"'
 endif
 
-PAGER_ENV_SQ = $(subst ','\'',$(PAGER_ENV))
-PAGER_ENV_CQ = "$(subst ",\",$(subst \,\\,$(PAGER_ENV)))"
-PAGER_ENV_CQ_SQ = $(subst ','\'',$(PAGER_ENV_CQ))
-BASIC_CFLAGS += -DPAGER_ENV='$(PAGER_ENV_CQ_SQ)'
-
 ALL_CFLAGS += $(BASIC_CFLAGS)
 ALL_LDFLAGS += $(BASIC_LDFLAGS)
 
@@ -2223,6 +2218,12 @@ builtin/help.sp builtin/help.s builtin/help.o: EXTRA_CPPFLAGS = \
 	'-DGIT_MAN_PATH="$(mandir_relative_SQ)"' \
 	'-DGIT_INFO_PATH="$(infodir_relative_SQ)"'
 
+PAGER_ENV_SQ = $(subst ','\'',$(PAGER_ENV))
+PAGER_ENV_CQ = "$(subst ",\",$(subst \,\\,$(PAGER_ENV)))"
+PAGER_ENV_CQ_SQ = $(subst ','\'',$(PAGER_ENV_CQ))
+pager.sp pager.s pager.o: EXTRA_CPPFLAGS = \
+	-DPAGER_ENV='$(PAGER_ENV_CQ_SQ)'
+
 version.sp version.s version.o: GIT-VERSION-FILE GIT-USER-AGENT
 version.sp version.s version.o: EXTRA_CPPFLAGS = \
 	'-DGIT_VERSION="$(GIT_VERSION)"' \