[SCons] Change prefix default if conda is detected

SConstruct

@@ -819,6 +819,9 @@ config["python_cmd"].default = sys.executable
 opts.AddVariables(*config.to_scons())
 opts.Update(env)
 opts.Save('cantera.conf', env)
+cantera_conf = []
+for line in open('cantera.conf'):
+    cantera_conf.append(line.strip())
 
 # Expand ~/ and environment variables used in cantera.conf (variables used on
 # the command line will be expanded by the shell)
@@ -866,10 +869,11 @@ except subprocess.CalledProcessError:
     env["git_commit"] = "unknown"
 
 # Print values of all build options:
-print("Configuration variables read from 'cantera.conf' and command line:")
-for line in open('cantera.conf'):
-    print('   ', line.strip())
-print()
+msg = ["Configuration variables read from 'cantera.conf' and command line:"]
+for line in cantera_conf:
+    msg.append(f"    {line}")
+msg.append("")
+logger.info("\n".join(msg), print_level=False)
 
 # ********************************************
 # *** Configure system-specific properties ***
@@ -1626,6 +1630,17 @@ if env['matlab_toolbox'] == 'y':
 # /usr/local because of dist-packages vs site-packages
 env['debian'] = any(name.endswith('dist-packages') for name in sys.path)
 
+# Check whether cantera should be installed into a conda environment
+conda_prefix = os.environ.get("CONDA_PREFIX")
+use_conda = False
+if conda_prefix is not None:
+    arg_list = set(line.split("=")[0].strip() for line in cantera_conf)
+    use_conda = not arg_list & {"prefix", "python_prefix", "python_cmd"}
+    use_conda &= sys.executable.startswith(conda_prefix)
+    if use_conda:
+        env["prefix"] = pjoin(conda_prefix, "Library")
+        logger.info(f"Using conda environment as default 'prefix': {env['prefix']}")
+
 # Directories where things will be after actually being installed. These
 # variables are the ones that are used to populate header files, scripts, etc.
 env['prefix'] = os.path.normpath(env['prefix'])