finance/*: set github.tarball_from explicitly

In preparation for changing the default.

finance/cgminer/Portfile

@@ -4,8 +4,9 @@ PortSystem       1.0
 PortGroup        github 1.0
 
 github.setup     ckolivas cgminer 4.10.0 v
+# Change github.tarball_from to 'releases' or 'archive' next update
+github.tarball_from tarball
 categories       finance
-platforms        darwin
 maintainers      nomaintainer
 license          GPL-3
 

finance/go-ethereum/Portfile

@@ -4,9 +4,10 @@ PortSystem          1.0
 PortGroup           github 1.0
 
 github.setup        ethereum go-ethereum 1.10.26 v
+# Change github.tarball_from to 'releases' or 'archive' next update
+github.tarball_from tarball
 
 categories          finance
-platforms           darwin
 license             GPL-3+ LGPL-3+
 maintainers         {umeshksingla @umeshksingla} openmaintainer
 description         Official Go implementation of the Ethereum protocol

finance/hledger-iadd/Portfile

@@ -5,6 +5,8 @@ PortGroup           github 1.0
 PortGroup           haskell_stack 1.0
 
 github.setup        hpdeifel hledger-iadd 2afeaadbbb29b339b48799ed2bd3112193d64f25
+# Change github.tarball_from to 'releases' or 'archive' next update
+github.tarball_from tarball
 version             1.3.21
 revision            0
 categories          finance haskell

finance/hledger/Portfile

@@ -5,6 +5,8 @@ PortGroup           github 1.0
 PortGroup           haskell_stack 1.0
 
 github.setup        simonmichael hledger 1.40
+# Change github.tarball_from to 'releases' or 'archive' next update
+github.tarball_from tarball
 revision            0
 categories          finance textproc haskell
 

finance/litecoin/Portfile

@@ -6,6 +6,8 @@ PortGroup           qt5 1.0
 PortGroup           boost 1.0
 
 github.setup        litecoin-project litecoin 0.16.3 v
+# Change github.tarball_from to 'releases' or 'archive' next update
+github.tarball_from tarball
 revision            11
 checksums           rmd160  aa2470a9e4f32c62953c5aae460471e0e3f1f801 \
                     sha256  0dccc577d704bd48226d11b749cca3bd7cadd23694ccbb15a87a0806704a69c3 \
@@ -29,7 +31,6 @@ long_description    Litecoin is a peer-to-peer Internet currency that enables in
                     It is unlikely for ASIC mining to be developed for Litecoin until the currency\
                     is widely used.
 
-platforms           darwin
 license             MIT
 
 homepage            https://litecoin.org

finance/portfolio-performance/Portfile

@@ -4,9 +4,10 @@ PortGroup               github 1.0
 PortGroup               java 1.0
 
 github.setup            buchen portfolio 0.50.3
+# Change github.tarball_from to 'releases' or 'archive' next update
+github.tarball_from     tarball
 name                    portfolio-performance
 categories              finance
-platforms               darwin
 license                 EPL-1
 maintainers             nomaintainer
 description             A simple tool to calculate the overall performance \