Stop generating implicit suffix rules in Makefiles

Suffix rules are the old-fashioned way of defining implicit rules for make.
We don't need them as we generate explicit rules for all sources we build.

[ChangeLog][qmake] Makefile output no longer contains implicit
suffix rules, as all sources are built using explicit rules.

Change-Id: I4ecfa5b80c8ae33aea8730836f3baf99dd4951dd
Task-number: QTBUG-30813
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>

3 files changed, 2 insertions, 22 deletions

diff --git a/qmake/generators/unix/unixmake2.cpp b/qmake/generators/unix/unixmake2.cpp
index 10b31def39..d0cd5d2354 100644
--- a/qmake/generators/unix/unixmake2.cpp
+++ b/qmake/generators/unix/unixmake2.cpp
@@ -298,17 +298,6 @@ UnixMakefileGenerator::writeMakeParts(QTextStream &t)
 
     /* rules */
     t << "first:" << (!project->isActiveConfig("no_default_goal_deps") ? " all" : "") << "\n";
-    t << "####### Implicit rules\n\n";
-    t << ".SUFFIXES: " << Option::obj_ext;
-    for(QStringList::Iterator cit = Option::c_ext.begin(); cit != Option::c_ext.end(); ++cit)
-        t << " " << (*cit);
-    for(QStringList::Iterator cppit = Option::cpp_ext.begin(); cppit != Option::cpp_ext.end(); ++cppit)
-        t << " " << (*cppit);
-    t << endl << endl;
-    for(QStringList::Iterator cppit = Option::cpp_ext.begin(); cppit != Option::cpp_ext.end(); ++cppit)
-        t << (*cppit) << Option::obj_ext << ":\n\t" << var("QMAKE_RUN_CXX_IMP") << endl << endl;
-    for(QStringList::Iterator cit = Option::c_ext.begin(); cit != Option::c_ext.end(); ++cit)
-        t << (*cit) << Option::obj_ext << ":\n\t" << var("QMAKE_RUN_CC_IMP") << endl << endl;
 
     if(include_deps) {
         if (project->isActiveConfig("gcc_MD_depends")) {
diff --git a/qmake/generators/win32/msvc_nmake.cpp b/qmake/generators/win32/msvc_nmake.cpp
index 31a9c53c90..a546e03b59 100644
--- a/qmake/generators/win32/msvc_nmake.cpp
+++ b/qmake/generators/win32/msvc_nmake.cpp
@@ -448,6 +448,8 @@ QStringList NmakeMakefileGenerator::sourceFilesForImplicitRulesFilter()
 
 void NmakeMakefileGenerator::writeImplicitRulesPart(QTextStream &t)
 {
+    t << "####### Implicit rules\n\n";
+
     t << ".SUFFIXES:";
     for(QStringList::Iterator cit = Option::c_ext.begin(); cit != Option::c_ext.end(); ++cit)
         t << " " << (*cit);
diff --git a/qmake/generators/win32/winmakefile.cpp b/qmake/generators/win32/winmakefile.cpp
index e6bf3388fa..1fba7057ab 100644
--- a/qmake/generators/win32/winmakefile.cpp
+++ b/qmake/generators/win32/winmakefile.cpp
@@ -570,7 +570,6 @@ void Win32MakefileGenerator::writeStandardParts(QTextStream &t)
     t << "DESTDIR_TARGET = " << fileVar("DEST_TARGET") << endl;
     t << endl;
 
-    t << "####### Implicit rules\n\n";
     writeImplicitRulesPart(t);
 
     t << "####### Build rules\n\n";
@@ -642,16 +641,6 @@ void Win32MakefileGenerator::writeObjectsPart(QTextStream &t)
 
 void Win32MakefileGenerator::writeImplicitRulesPart(QTextStream &t)
 {
-    t << ".SUFFIXES:";
-    for(QStringList::Iterator cppit = Option::cpp_ext.begin(); cppit != Option::cpp_ext.end(); ++cppit)
-        t << " " << (*cppit);
-    for(QStringList::Iterator cit = Option::c_ext.begin(); cit != Option::c_ext.end(); ++cit)
-        t << " " << (*cit);
-    t << endl << endl;
-    for(QStringList::Iterator cppit = Option::cpp_ext.begin(); cppit != Option::cpp_ext.end(); ++cppit)
-        t << (*cppit) << Option::obj_ext << ":\n\t" << var("QMAKE_RUN_CXX_IMP") << endl << endl;
-    for(QStringList::Iterator cit = Option::c_ext.begin(); cit != Option::c_ext.end(); ++cit)
-        t << (*cit) << Option::obj_ext << ":\n\t" << var("QMAKE_RUN_CC_IMP") << endl << endl;
 }
 
 void Win32MakefileGenerator::writeBuildRulesPart(QTextStream &)