First of all, I also agree that the best for FPC compiler and Lazarus IDE is to continue by themselves just as it is.
This thread was started on 29 May 2008 and its questioner seems to have disappeared since 2008:
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Simmo8 - New member
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Date Registered: March 28, 2008, 07:30:53 pm
Local Time: February 19, 2017, 11:16:03 am
Last Active: June 04, 2008, 04:52:15 pm
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Just for the record, the original open sourced Dev-C++ IDE and its forks Orwell Dev-C++ IDE and wxDev-C++ IDE are IDEs for C++ were developed using Delphi 6 and 7.
https://en.wikipedia.org/wiki/Dev-C%2B%2Bhttp://www.bloodshed.net/devcpp.htmlDev-C++ 5 (currently beta)
Bloodshed Dev-C++ is a full-featured Integrated Development Environment (IDE) for the C/C++ programming language. It uses Mingw port of GCC (GNU Compiler Collection) as it's compiler. Dev-C++ can also be used in combination with Cygwin or any other GCC based compiler.
Source code : Delphi 6 Source code of Dev-C++ is available for free under the GNU General Public License (GPL)
http://orwelldevcpp.blogspot.com.br/-------------
SOURCE 5.11.7z/Source/README.txt
1. Compiling devcpp.exe
...
This process has only been tested using Delphi 6 and Delphi 7. The code base
should be compatible with more recent versions of Delphi, but there is no
guarantee anything will work. 27/04/2015
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So, obviously, as a matter of choice, anyone can use any compiler and any IDE to build any new compiler or any new IDE.