Configure: fixed make macros to use parentheses instead of braces.

Parentheses are more portable, in particular they are understood by nmake
while braces aren't.

auto/install

diff --git a/auto/install b/auto/install
index 6ef0da9..254f9bc 100644
--- a/auto/install
+++ b/auto/install
@@ -8,7 +8,7 @@
     cat << END                                                >> $NGX_MAKEFILE
 
 install_perl_modules:
-	cd $NGX_OBJS/src/http/modules/perl && \${MAKE} install
+	cd $NGX_OBJS/src/http/modules/perl && \$(MAKE) install
 END
 
     NGX_INSTALL_PERL_MODULES=install_perl_modules

auto/lib/libatomic/make

diff --git a/auto/lib/libatomic/make b/auto/lib/libatomic/make
index f3cd832..023ed18 100644
--- a/auto/lib/libatomic/make
+++ b/auto/lib/libatomic/make
@@ -6,7 +6,7 @@
     cat << END                                            >> $NGX_MAKEFILE
 
 $NGX_LIBATOMIC/src/libatomic_ops.a:	$NGX_LIBATOMIC/Makefile
-	cd $NGX_LIBATOMIC && \${MAKE}
+	cd $NGX_LIBATOMIC && \$(MAKE)
 
 $NGX_LIBATOMIC/Makefile:	$NGX_MAKEFILE
 	cd $NGX_LIBATOMIC && ./configure

auto/lib/perl/make

diff --git a/auto/lib/perl/make b/auto/lib/perl/make
index 248be9e..5f13bb2 100644
--- a/auto/lib/perl/make
+++ b/auto/lib/perl/make
@@ -12,7 +12,7 @@
 		$NGX_OBJS/src/http/modules/perl/Makefile
 	cp -p src/http/modules/perl/nginx.* $NGX_OBJS/src/http/modules/perl/
 
-	cd $NGX_OBJS/src/http/modules/perl && \${MAKE}
+	cd $NGX_OBJS/src/http/modules/perl && \$(MAKE)
 
 	rm -rf $NGX_OBJS/install_perl